Black screen flickering and [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

Maybe related to https://bugs.launchpad.net/bugs/1451632

See recording on http://tinypic.com/r/2wpt74m/9 (glitches where not visible on a direct screen grab)

With the previous kernel I don't see the glitches nor the i915 underruns
$ uname -a
Linux river 4.2.0-27-generic #32-Ubuntu SMP Fri Jan 22 04:49:08 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
$ dmesg | grep i915
[ 2.698444] [drm] Initialized i915 1.6.0 20150522 for 0000:00:02.0 on minor 0
[ 2.763865] [drm] GMBUS [i915 gmbus dpb] timed out, falling back to bit banging on pin 5
[ 3.498858] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 3.498859] i915 0000:00:02.0: registered panic notifier

Maybe a duplicate of https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1522922 ... weird that it only occurs in the latest kernel package

Ah, thanks for pointing out the BIOS update. However it didn't change anything related to the issue.

$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
8DET70WW (1.40 )
05/14/2015

The flickering is also present for me in the latest mainline
$uname -a
Linux river 4.4.3-040403-generic #201602251634 SMP Thu Feb 25 21:36:25 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
$ dmesg | grep i915
[ 2.538980] i915: unknown parameter 'lvds_downclock' ignored
[ 2.778824] [drm] Initialized i915 1.6.0 20151010 for 0000:00:02.0 on minor 0
[ 4.319937] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 69.185831] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[ 69.186167] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
[ 69.186184] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun

since lvds_downclock is mentioned I wanted to point out my power saving options:
$ cat /etc/modprobe.d/i915.conf
options i915 enable_rc6=1 enable_fbc=1 lvds_downclock=1 semaphores=1

However removing them doesn't change anything

Hubert Hesse, in order to allow additional upstream developers to examine the issue, at your earliest convenience, could you please test the latest upstream kernel available from http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D ? Please keep in mind the following:
1) The one to test is at the very top line at the top of the page (not the daily folder).
2) The release names are irrelevant.
3) The folder time stamps aren't indicative of when the kernel actually was released upstream.
4) Install instructions are available at https://wiki.ubuntu.com/Kernel/MainlineBuilds .

If testing on your main install would be inconvenient, one may:
1) Install Ubuntu to a different partition and then test this there.
2) Backup, or clone the primary install.

If the latest kernel did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this issue is fixed in the mainline kernel, please add the following tags by clicking on the yellow circle with a black pencil icon, next to the word Tags, located at the bottom of the report description:
kernel-fixed-upstream
kernel-fixed-upstream-X.Y-rcZ

Where X, and Y are the first two numbers of the kernel version, and Z is the release candidate number if it exists.

If the mainline kernel does not fix the issue, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-X.Y-rcZ

Please note, an error to install the kernel does not fit the criteria of kernel-bug-exists-upstream.

Once testing of the latest upstream kernel is complete, please mark this report's Status as Confirmed. Please let us know your results.

Thank you for your understanding.

Hi Christopher,

4.5 rc5 has indeed fixed the issue for me. Thanks a lot :)

$ uname -a
Linux river 4.5.0-040500rc5-generic #201602201730 SMP Sat Feb 20 22:32:16 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ dmesg | grep i915
[ 2.513449] i915: unknown parameter 'lvds_downclock' ignored
[ 2.743658] [drm] Initialized i915 1.6.0 20151218 for 0000:00:02.0 on minor 0
[ 4.275935] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 5.396543] snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])

Ah no, I was to quick to judge. Now the error occurred with 4.5rc5, but it is less frequent. And the quality of the glitches change.
No more repetition errors, just "regular" graphic errors.

$ dmesg | grep i915
[ 2.513449] i915: unknown parameter 'lvds_downclock' ignored
[ 2.743658] [drm] Initialized i915 1.6.0 20151218 for 0000:00:02.0 on minor 0
[ 4.275935] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 5.396543] snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ 1027.095396] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[ 1027.095477] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
[ 1027.095530] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun

Hubert Hesse, the next step is to fully commit bisect from kernel 4.2.0-27 to 4.2.0-30 in order to identify the last good kernel commit, followed immediately by the first bad one. This will allow for a more expedited analysis of the root cause of your issue. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection ?

Please note, finding adjacent kernel versions is not fully commit bisecting.

After the offending commit (not kernel version) has been identified, then please mark this report Status Confirmed.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

So it turn out when I rebuild the package for 4.2.0-27 I already see that glitches occurring in that specific kernel version. So it look like there is difference between the package I built and the official package or I screwed up the build process?

Here is what I did, I have to say the wik page you linked was very verbose. I know what git bisect works, however I don't how to build a Ubuntu kernel package (kteam-tools produced some errors for me)

I took the steps from https://wiki.ubuntu.com/KernelTeam/GitKernelBuild#Using_Ubuntu_Kernel_Configuration
Can you check if those steps should produce a correct package?

sudo apt-get install git build-essential kernel-package fakeroot libncurses5-dev libssl-dev ccache --no-install-recommends # because of texlive

git clone git://kernel.ubuntu.com/ubuntu/ubuntu-wily.git
cd ubuntu-wily/
cp -a /usr/share/kernel-package ubuntu-package

cp debian/control-scripts/{postinst,postrm,preinst,prerm} ubuntu-package/pkg/image/
cp debian/control-scripts/headers-postinst ubuntu-package/pkg/headers/

# set up ccache because I thought this will save time while bisecting -- however mostly cache misses
vim ~/.bashrc
if [ -d /usr/lib/ccache ]; then
        export PATH=/usr/lib/ccache:"${PATH}"
        export CCACHE_NLEVELS=5
fi
ccache -M 10G

cp /boot/config-4.2.0-27-generic .config
make localmodconfig # because building all modules takes forever
make oldconfig

CONCURRENCY_LEVEL=`getconf _NPROCESSORS_ONLN` fakeroot make-kpkg --initrd --append-to-version=-custom --overlay-dir=$(pwd)/ubuntu-package kernel_image kernel_headers

cd ..
dpkg -i *.deb

#git tag --list
#git bisect start
#git bisect good Ubuntu-4.2.0-27.32
#git bisect bad Ubuntu-4.2.0-30.36
# Here I did noticed that after the 6 commits all commits where bad. Then I checked the assumption that "Ubuntu-4.2.0-27.32" was good, it was not

any news on this?

Can anyone confirm the steps I took where all right?
What's the difference between the kernel I compiled and the officially distributed one (4.2.0-27)? Any patches to reproduce the official binary?

Same problem for me. I can easily reproduce a problem my moving mouse over youtube video borders. If it's needed I can record a video. Should I do that?

Still happening on Xenial with latest distro kernel:

[ 12.777803] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[ 12.777826] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

Linux hkgofdt02 4.4.0-21-generic #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04 LTS
Release: 16.04
Codename: xenial

What can I do to help determine the cause of a problem or fix it?

See https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1522922 Nothing really, except to stick with 4.1.21

Also a funny glitches happen with Google Documents very often.

PocketSam, it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

Christopher, I hope I did everything right.
Here is my new bug report:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1577099

I'm still seeing the issue with latest:
http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-next/current/
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.10-xenial/
Where other people report the issues are fixed for them

However not as severe as with 4.2.0-30.36

Can someone please advise what to do? My questions from #14 are still unaddressed:
Can anyone confirm the steps I took where all right?
What's the difference between the kernel I compiled and the officially distributed one (4.2.0-27)? Any patches to reproduce the official binary?

Hi all, I was bugged by this both in Ubuntu 16.04 (any 4.4 kernel after release) and in ArchLinUX with all actual 4.5 kernels.
My solution was to take the 4.6 kernel on ArchLinUX (testing repository), after which I was cured from all difficulties. If you use VirtualBox with a new 4.4/4.5 kernel in your client, you get very often bugged by this failure.
--> If you can, use LinUX kernel 4.6.

I can also confirm that upgrading to 16.04 and using a 4.6 kernel (http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.6-yakkety/) solves the issue for me.

Hubert Hesse, the next step is to fully reverse commit bisect from kernel 4.5-rc5 to 4.6 in order to identify the last bad commit, followed immediately by the first good one. Once this good commit has been identified, it may be reviewed for backporting. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection#How_do_I_reverse_bisect_the_upstream_kernel.3F ?

Please note, finding adjacent kernel versions is not fully commit bisecting.

After the fix commit (not kernel version) has been identified, then please mark this report Status Confirmed.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

If I understand correctly we should install different linux kernel versions untill we find a kernel, that fixes bug?
I'm a bit confused what link I should use to sort out kernels. Can you suggest, please?
Try kernels from http://kernel.ubuntu.com/~kernel-ppa/mainline/ from v 4.4 to 4.6. ?

@Christopher To demand a full bisect for the status "confirmed" is IMHO much over the edge, especially as it takes some time to trigger the bug.

@PocketSam Although Chrisopher's advice is right to follow, if you gather the information with which mainline kernel the bug disapers it would still be good. And you don't need so much technical background or time in my case ;)

Linux xenie 4.4.0-24-generic #43-Ubuntu SMP
Intel® Core™ i3-4160 CPU @ 3.60GHz × 4
Ubuntu 16.04 LTS 64 bit

[Út čen 14 00:11:03 2016] vboxpci: IOMMU not found (not registered)
[Út čen 14 00:11:03 2016] nf_conntrack: automatic helper assignment is deprecated and it will be removed soon. Use the iptables CT target to attach helpers instead.
[St čen 15 00:18:28 2016] perf interrupt took too long (2512 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
[St čen 15 01:37:31 2016] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe A
[St čen 15 01:37:31 2016] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[St čen 15 01:40:53 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: ELD buf size is 0, force 128
[St čen 15 01:40:53 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD data byte 0
[St čen 15 02:08:53 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: ELD buf size is 0, force 128
[St čen 15 02:08:53 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD data byte 0
[St čen 15 02:08:55 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: ELD buf size is 0, force 128
[St čen 15 02:08:55 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD data byte 0
[St čen 15 19:56:52 2016] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe A
[St čen 15 19:56:52 2016] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[St čen 15 20:28:09 2016] usb 3-9.1: USB disconnect, device number 3

@pavel See https://wiki.ubuntu.com/Kernel/MainlineBuilds and try which newer kernel solves the issue.

While much less frequent than when using a 4.4 kernel, the problem still occurs for me when using a 4.6 kernel:

uname -a
4.6.0-040600-generic #201606030904 SMP Fri Jun 3 13:06:01 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

dmesg
[31606.245708] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[31606.245846] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
[40612.123848] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[40612.123987] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun

Ubuntu 16.04 LTS
Intel(R) Core(TM) i5 CPU M 520
Thinkpad T410

Happens the same with 4.4.0-24-generic

I was having this same problem running kernel 4.4.0-28-generic in 16.04. Upgrading to kernel 4.6.3-040603-generic seems to have resolved the problems (or at least made it rare enough that I don't notice it anymore). On 4.4 the graphic errors were particular common (every few seconds) when using gotomeeting or other video chat web sites that use WebRTC via Google Chrome (with Chrome video acceleration turned off). The screen going blank for 1 second problem seemed particularly common when alt-tabbing between Gnome Terminal instances. The "*ERROR* CPU pipe A FIFO underrun" in dmesg has also stopped.

Correct to my previous comment. After running on kernel 4.6.3-040603-generic I do still see the "funny repetition patterns (back in time glitches)", but it seems less frequent. The other problems (black screen and buffer underrun in dmesg) have not recurred.

I actually switch back to my x230 and don't have the hardware for testing, but we should really bisect this issue so the current xenial kernel can be fixed.

Anyone who wants to help can test those kernels https://wiki.ubuntu.com/Kernel/MainlineBuilds especially the late 4.4 and the early 4.5 i guess the fix came in between. Just install and reboot :)

I don't see the need for a bisect. To quote https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1522922/comments/125
"There's one thing I still don't understand... the root of the problem was identified in https://bugs.freedesktop.org/show_bug.cgi?id=91393#c25"

The associated patch http://patchwork.freedesktop<email address hidden> revert two commits identified there.
These have to backported to archive the same experience as on the latest 4.6

My original question from #14 remains
Can anyone confirm the steps I took where all right?
What's the difference between the kernel I compiled and the officially distributed one (4.2.0-27)? Any patches to reproduce the official binary?

@Hubert Of course it doesn't need a bisect when you already know the commit the fixes it :) But i would sugest that we try to get it fixed in xenial's kernel first. Unfortunately i can't assign the kernel team, can you help out here?

bhat3, unfortunately, we don't know if the commit fixes it, as it hasn't been tested on the original reporter's (Hubert Hesse) hardware.

Hubert Hesse, regarding your question, bisecting the Ubuntu kernel can be tricky, hence you are better off refocusing onto the reverse bisect of the mainline kernel to confirm the fix commit, and reverting it causes the issue again.

@penalvch Thanks for the info, but can you assist us on how to test and get a fix in xenial's kernel. I am out of kernel packaging since 2.6.33 and want to help to make xenial working on Thinkpads with docking stations.

bhat3, if one thinks they have identified a fix commit, they may test it via https://wiki.ubuntu.com/Kernel/KernelBisection#Testing_a_newly_released_patch_from_upstream .

@penalvch I understand and would like to identify it, but unfortunately i can't trigger that bug on neither my x220 nor my x230 while all T450s should have problems with external display and docking stations. With linux-*-lts-* packages it will at least be resolved at least in autum :)

bhat3 - I'm seeing the problem after upgrading to current 16.10. What do you wan't me to try out on my system to track down the bug?

Since upgrading to 16.04 on an X250 and T450s, I have had screen blanking issues with external displays on both machines. When the screen is more "active", such as when watching YouTube, the screen would go blank for 2 - 3 secs, then come to life again. The more "active" screen is the one that would blank.

I would see related kernel messages (IFO underrun) sometimes, but not always.

I've just spent some time testing various kernels and can report that 4.6.7 (wily) is working well for me and the screen blanking issue is finally gone! Bliss.

Happy to do more testing if it helps anyone.

gdi2k, can you provide what kernel version did you test before 4.6.7 that had this bug?

gdi2k, it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

I'm experiencing the exact same issues, especially those of https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1550779/comments/43.

Upgraded from 15.10 to 16.04 (Linux 4.4.0-36-generic #55-Ubuntu SMP Thu Aug 11 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
)

This makes my machine unusable and I'll have to revert to 15.10.

Machine is a Dell Latitude e6410 Laptop.

123vier (flowrist), it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

I just took some updates to a number of graphic libraries on 16.04, and now I can't login to kubuntu. The symptom is that it takes my password on the greeter screen, but never updates the screen after that.

The messages include these apparently related kernel messages:
kernel: [ 701.564034] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe B
kernel: [ 701.564054] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

It is, of course, unclear whether these libraries triggered the kernel bug or if this is unrelated to the kernel bug. I attached it here because this is what I noticed first.

I'm currently running kernel 4.4.0-36.

Here are my most recent updates. The problem started after I rebooted. Of course that was the next time I logged in too...

Start-Date: 2016-09-07 08:46:04
Commandline: /usr/bin/unattended-upgrade
Remove: libcdaudio1:amd64 (0.99.12p2-14), linux-image-extra-4.2.0-36-generic:amd64 (4.2.0-36.42), linux-image-extra-4.4.0-22-generic:amd64 (4.4.0-22.40), gtk2-engines-murrine:amd64 (0.98.2-0ubuntu2.1), linux-image-extra-4.4.0-24-generic:amd64 (4.4.0-24.43), libslv2-9:amd64 (0.6.6+dfsg1-3build1), linux-image-extra-4.4.0-28-generic:amd64 (4.4.0-28.47), linux-image-extra-4.4.0-31-generic:amd64 (4.4.0-31.50), libfaac0:amd64 (1.28+cvs20151130-1)
End-Date: 2016-09-07 08:48:13

Start-Date: 2016-09-07 16:42:27
Install: libgnome-keyring-common:amd64 (3.12.0-1build1, automatic), libgnome-keyring0:amd64 (3.12.0-1build1, automatic)
Upgrade: libgles2-mesa:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libgles1-mesa:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libglapi-mesa:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libglapi-mesa:i386 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), p11-kit:amd64 (0.23.2-3, 0.23.2-5~ubuntu16.04.1), libxatracker2:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libegl1-mesa-drivers:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libegl1-mesa:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libegl1-mesa:i386 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), p11-kit-modules:amd64 (0.23.2-3, 0.23.2-5~ubuntu16.04.1), libgbm1:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libgbm1:i386 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), cups-filters:amd64 (1.8.3-2ubuntu3, 1.8.3-2ubuntu3.1), chromium-browser:amd64 (51.0.2704.79-0ubuntu0.16.04.1.1242, 52.0.2743.116-0ubuntu0.16.04.1.1250), libcupsfilters1:amd64 (1.8.3-2ubuntu3, 1.8.3-2ubuntu3.1), chromium-codecs-ffmpeg-extra:amd64 (51.0.2704.79-0ubuntu0.16.04.1.1242, 52.0.2743.116-0ubuntu0.16.04.1.1250), libwayland-egl1-mesa:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libfontembed1:amd64 (1.8.3-2ubuntu3, 1.8.3-2ubuntu3.1), libgl1-mesa-dri:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libgl1-mesa-dri:i386 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), cups-filters-core-drivers:amd64 (1.8.3-2ubuntu3, 1.8.3-2ubuntu3.1), libgl1-mesa-glx:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libgl1-mesa-glx:i386 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), libp11-kit0:amd64 (0.23.2-3, 0.23.2-5~ubuntu16.04.1), libp11-kit0:i386 (0.23.2-3, 0.23.2-5~ubuntu16.04.1), mesa-vdpau-drivers:amd64 (11.2.0-1ubuntu2.1, 11.2.0-1ubuntu2.2), chromium-browser-l10n:amd6...

Alan Robertson, it will help immensely if you filed a new report with Ubuntu by ensuring you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information running the following from a terminal:
ubuntu-bug xorg

Also, please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

Christopher M Penalver: There is an AskUbuntu issue for my particular problem - something a lot like it - you can find it here: http://askubuntu.com/questions/765364/kubuntu-16-04-sddm-login-screen-hangs I've asked if they also saw the CPU underrun - no answer yet.

FWIW, I just installed xdiagnose and enabled all 3 debug check boxes, and it doesn't show any errors at the moment. I've worked around the "can't login" problem at the moment, and xdiagnose doesn't show any errors.

Of course, if I hadn't worked around the "can't login" part, then I wouldn't have been able to launch xdiagnose to diagnose the X windows problem ;-).

I will do as you suggested and create the additional bug report - and will link to it here and add you to the bug report.

After a couple of days with linxu 4.8.0 the problems are seems to be gone. I just hope that it is an effect of a real change and not a timing issue.

4.4.0-38 seems to have done most of it for me. Could it have been resolved in another package?
I only have FIFO underrun on pipe B when I check my dmesg (running for 4 days). However, my computer is a macbook pro that needs to go around Apple soon for other hardware issues, so i'm not sure to trust it.

Issue is also gone for me since the latest kernel update to 4.4.0-38, thanks to everyone involved!

I'm seeing this behavior on my Thinkpad x260:

[123678.466040] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[123742.876516] [drm:intel_pipe_update_end [i915]] *ERROR* Atomic update failure on pipe A (start=214815 end=214816) time 150 us, min 1073, max 1079, scanline start 1070, end 1080

$ uname -a
Linux flartchops 4.8.0-26-generic #28-Ubuntu SMP Tue Oct 18 14:39:52 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Caige Nichols (caiges), it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

@penalvch: I believe I'm experiencing the same issue. I've filed a report where I've posted the results of ubuntu-bug linux.

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1645876

I'll subscribe you to it if you aren't already on it.

I see the same issue on 17.04 running kernel 4.10.0-21

Firefox seems perfectly stable, but running other apps like Gnome-Terminal, VLC and others I see black boxes, flashes and bars across the screen. Often they come and go in a flash, but sometimes the whole screen goes and the laptop shuts down (not gracefully - nothing in the logs, seems like a sudden power cut).

dmesg shows a message about under run each time the graphical glitches are seen:

"[10126.284724] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[28144.138412] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[55259.892080] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[68189.763709] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[68998.747340] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
"

I am happy to troubleshoot this, please someone make suggestions!!

Chris (chrisonbuntu), it will help immensely if you use the computer the problem is reproducible with, and file a new report with Ubuntu by using the default repository kernel (not mainline/upstream/3rd party) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

Hi Chris (penalvch) - i have done as you asked.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1695989
you should be subscribed to it.

Hello all, (I wrote this on my bug report - here too so people see it!!)

OK. Good news - 4.12-0rc4 seems very stable (visually at least)

I have opened 3 terminal windows, have them running 'top' and other commands so the window contents get updated, dragged them so they hang half off the bottom of the screen... 30 mins so far and no crashes, no black glitches.

dmesg is free of FIFO buffer underrun messages too.

I will leave the laptop running 4.12 kernel for a couple of days to see if there are any other issues. Let me know if you want me to share any logs etc with you.

Tested it yesterday.
Had this bug with kubuntu 16.04.2 after kernel update and later on with an update to kubuntu 17.04.

With 4.12.0-041200rc4-generic #201706042031 graphics/KDE works fine,

Installed the "all" headers and the kernel deb.

but this specific error is still listed in dmesg:
[ 3.872945] Console: switching to colour frame buffer device 160x50
[ 3.892060] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 5.137529] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

Update for those not following my other bug report (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1695989)

I found the bug in all the 4.11 and 4.10, but not 4.12rc1 or 4.12rc4.

NOTE - @Jochen - I dont see the FIFO underrun error while running the 4.12 kernel.

@Chris; by starting my Dell Latitude 6410 this morning I see this FIFO underrun error again booting into emergency mode.

Using 4.12rc4.

This is strange, because last Friday and Saturday I did not have any problems.

Tried other distros and Kernel versions.
I can only boot to emergency mode.

Hardware problem...seems to me.
Memtest + HDD test etc marks no errors or failures

The system is only stable in graphics mode right after installation.

Still seeing the error message on the following setup:

- Kernel: 4.12.0-041200-generic (downloaded from http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.12/)
- Ubuntu 17.04
- ThinkStation P310

[ 1130.350050] drm: not enough stolen space for compressed buffer (need 29491200 more bytes), disabling. Hint: you may be able to increase stolen memory size in the BIOS to avoid this.
[ 1130.433925] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[ 1130.434005] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
[ 1146.868877] [drm] Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS.

If I get the problem again, are any specific log files of interest?

I'm on kernel 4.13 and got this error message as well.
The external monitor connected to laptop (Razer Blade Stealth) flickers a lot.

Just an update, setting a `i915.enable_rc6=0` kernel parameter helps and the issue is gone but, as this switches of CPU and GPU energy saving, it's rather a temporary workaround not a final solution.

Kernel 4.13.2 working ok for me, run for an hour without issue so far. Will report back after more testing.

I hope 4.13 kernels will work well, they will be in the Ubuntu 17.10 series and it would be nice to get back off the mainline kernels!

Kernel 4.13.2 working fine for 2 days...

I've just tried 4.13.2, screen is still blinking while on with the default i915.enable_rc6=1.

There is an improvement though. On the kernel version 4.13 my laptop was totally crashing after hitting caps-lock twice. Now this ridiculous one is at least gone.

Although I still need to keep the rc6=0 flag at kernel boot params to prevent screen flickering (an external one, connected via HDMI).

I see graphic errors on external monitors and following messages in logs with 4.13.0 kernel. Errors appear after laptop works for 3-4 days without reboot.

kernel: [173125.746076] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe A
kernel: [173125.746104] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
kernel: [173125.795556] [drm:intel_check_cpu_fifo_underruns [i915]] *ERROR* fifo underrun on pipe B

Ubuntu 17.10, hardware is Dell Latitude E5540

I started seeing computer lockups with kernel 4.13.0 reporting a "fifo underrun on pipe B" when a multiple monitor setup enters power save state. It's nearly 100% reproducible. No issues with just the laptop screen, without an external monitor.

I've just upgraded to 17.10. As 4.13.2 is reported to resolve some issues above, is is on the way to the distros?

I have the same problem.

XUbuntu 17.04 with kernel 4.13.0-17-generic #20-Ubuntu SMP Mon Nov 6 10:04:08 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Dec 6 18:06:47 HOSTNAME kernel: [205433.429560] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe C FIFO underrun

I have the same or a similar problem on kernel version 4.13.4, Ubuntu 17.10.

Not sure whether it is exactly the same though. In syslog I see the FIFO underrun message is preceded by a lot of other ERROR messages:

Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.055663] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.055726] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.072359] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.072425] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.089055] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.089122] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.105722] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.105788] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.112465] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.139057] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080
Dec 26 14:33:59 ruben-Precision-5520 kernel: [ 4152.139116] [drm:gen8_irq_handler [i915]] *ERROR* Fault errors on pipe A: 0x00000080

Same issue here, DELL XPS 15 9560, I noticed the error because my Gnome Lock screen clock "stops" at the point when I locked my screen.

Ubuntu 16.04, 4.13.0-26-generic

Looking at journalctl, the last message before the clock stopped is "Jan 15 10:21:05 hamide-XPS kernel: [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe C FIFO underrun"

I see the problem on my Thinkpad T450 when I connect external display on 16.04 LTS with Linux kernel 4.13.0-26-generic:

dmesg -T | grep i915
[Thu Jan 18 15:24:30 2018] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[Thu Jan 18 15:24:30 2018] [drm] Initialized i915 1.6.0 20170619 for 0000:00:02.0 on minor 0
[Thu Jan 18 15:24:31 2018] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[Thu Jan 18 15:24:37 2018] snd_hda_intel 0000:00:03.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[Thu Jan 18 16:05:48 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:07:26 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:20 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:22 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:56 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:31:29 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:31:37 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:35:19 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

Not sure what's the workaround. I don't see the problem when I use laptop's display.

Same issue here on a Lenovo T450s with a Intel HD Graphics 5500 (Broadwell GT2) GPU. It happens both with Ubuntu 16.04 and Fedora (26 and 27) so I suppose that's a weird bug in the intel driver.
It also happens sometimes without any external monitor when I leave my notebook powered up during the night: in the moring my gdm lock screen flickers and I'm unable to login into my session.
Has someone found a workaround or a fix?

I'm currently at kernel version 4.14.11 and the intel firmware drivers installed from
https://01.org/linuxgraphics/downloads/firmware
which are:
kbl_guc_ver9_14.bin
bxt_guc_ver8_7.bin
kbl_dmc_ver1_01.bin

And the bug is still there. Although it wasn't manifesting itself until I've connected an external screen (may coincidence though).

@Angelo Lisco
Not sure will it help in your case but have you tried setting kernel boot flag?
i915.enable_rc6=0

It's workaround not a fix, I'm afraid.

I keep experiencing this issue, using Ubuntu 17.10, an Intel Core i3-5005U (with Intel HD 5500). It appears most often when a new notification comes in (Slack/Spotify) and the lockscreen is visible.

From dmesg:
[Fri Feb 23 13:51:50 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

$ uname -a
Linux uk-it-033 4.13.0-36-generic #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

If you need any further information, please let me know.

I'm testing Xubuntu 18.04 and have the same message in kern.log:

Mar 15 17:26:21 Xubuntu-18-04 kernel: [ 543.782137] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

I have experienced some "weird" screens.Please have a look here: http://i.imgur.com/x2vCDj3.png

Running uname -a gives:

Linux Xubuntu-18-04 4.15.0-12-generic #13-Ubuntu SMP Thu Mar 8 06:24:47 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Please let me know if you need more information.

For Intel GLK user: There is a upstream bug opened and fixed: https://bugs.freedesktop.org/show_bug.cgi?id=100302

And this patch works for me on Intel Gemini Lake platform: https://github.com/torvalds/linux/commit/ed69cd40685c949ec9c65701758bbf9e6840240f

This patch is merged starting from v4.15-rc1

@Tomasz Przybysz
i915.enable_rc6=0 as a workaround doesn't seem to work.

I have similar symptoms as Angelo Lisco. I leave laptop on overnight and sometimes in the morning it got frozen with same underrun error message in logs.

enable_rc6 is definitely set to 0:
$ cat /sys/class/drm/card0/power/rc6_enable
0

And the bug is still there with kernel 4.15.10 =( just a heads up

This still occurs for me on kernel 4.15.12.

Like others, this still occurs on 4.15.13-041513-lowlatency with a clean install of 16.04.

However, please note: It ONLY occurs if I am connected from my laptop's docking station (HP 840 G2) to an external monitor (HDMI or DVI same issue), AND the laptop lid is DOWN.

If the above is true i get the same error, or the funny graphics, etc.

However, if i keep the laptop lid OPEN, even though i am still connected to the external screen, i have NO problem booting up.

For me this manifests in lockups. The hardware buttons on my laptop still work, fans etc. but xorg basically hard locks (Kernel 4.15.12)

For me this manifests in lockups. The hardware buttons on my laptop still work, fans etc. but xorg basically hard locks (Kernel 4.15.12). There is no monitor in play.

I am running Ubuntu 18.04 since about a month. No problems so far, until i made an update 2 or 3 days ago. Since then i have the same problem. Messages in dmesg with underrun, flickering screen etc.
It happens all the time. This happens on my htpc so i am not able to watch TV longer than 5-10 minutes, then it starts again with flickering.
I also tried that rc6_enable-workaround, did not help.
Any help is appreciated!

Still happening on 4.16.6 kernel for me.

I have been experiencing this kind of problem (with intel_cpu_fifo_underrun_irq_handler in syslog) for a couple of weeks now on Ubuntu 17.10 (4.13.0-39-generic). Here's the syslog extract:

    May 9 13:18:57 xx zeitgeist-datah[2322]: recent-manager-provider.vala:106: (null) was not registered in RecentInfo item 0x55b07472c020
    May 9 13:19:58 xx kernel: [834627.678287] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
    May 9 13:19:58 xx /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): EDID vendor "FUS", prod id 1957
    May 9 13:19:58 xx /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): Using hsync ranges from config file
    May 9 13:19:58 xx /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): Using vrefresh ranges from config file
    May 9 13:19:58 xx /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): Printing DDC gathered Modelines:
    May 9 13:19:58 xx /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): Modeline "1920x1080"x0.0 148.50 1920 2008 2052 2200 1080 1089 1095 1125 +hsync +vsync (67.5 kHz eP)
    May 9 13:19:58 sanchopansa09 /usr/lib/gdm3/gdm-x-session[1843]: (II) modeset(0): Modeline "800x600"x0.0 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e)

Mostly the secondary screen goes (and stays) black when this happens, sometimes the primary notebook (Lenovo) screen. Interestingly, the secondary screen usually comes back when I open “change background” from the context menu (on the primary screen). I need not actually change the background, just open “change background.”

Often when the screen starts flickering and goes black there is the sound of really heavy disk activity, maybe more than justifiable by sys-logging.

Still happening on kernel 4.15.0-24
Xubuntu 18.04 LTS
Lenovo ThinkPad T480 on a dock and DP monitor connected.

Both screens go black when trying to unlock the session and I have to restart the laptop.

[ 17.172263] snd_hda_intel 0000:00:0e.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ 17.177437] EDAC pnd2: b_cr_tolud_pci=080000001 ret=0
[ 17.177495] EDAC pnd2: b_cr_touud_lo_pci=000000000 ret=0
[ 17.177536] EDAC pnd2: b_cr_touud_hi_pci=000000001 ret=0
[ 17.177577] EDAC pnd2: b_cr_asym_mem_region0_mchbar=000000000 ret=0
[ 17.177619] EDAC pnd2: b_cr_asym_mem_region1_mchbar=000000000 ret=0
[ 17.177659] EDAC pnd2: b_cr_mot_out_base_mchbar=000000000 ret=0
[ 17.177700] EDAC pnd2: b_cr_mot_out_mask_mchbar=000000000 ret=0
[ 17.177781] EDAC pnd2: b_cr_slice_channel_hash=80000d8c00000245 ret=0
[ 17.177823] EDAC pnd2: b_cr_asym_2way_mem_region_mchbar=000000000 ret=0
[ 17.177865] EDAC pnd2: d_cr_drp0=04488c091 ret=0
[ 17.177907] EDAC pnd2: d_cr_drp0=04488c091 ret=0
[ 17.177948] EDAC pnd2: d_cr_drp0=000000000 ret=2
[ 17.177988] EDAC pnd2: d_cr_drp0=000000000 ret=2
[ 17.177989] EDAC pnd2: Unsupported DIMM in channel 0
[ 17.177990] EDAC pnd2: Unsupported DIMM in channel 1
[ 17.177991] EDAC pnd2: Failed to register device with error -22.
[ 17.217570] intel_telemetry_core Init

[ 52.411051] logitech-hidpp-device 0003:046D:4024.000C: input,hidraw2: USB HID v1.11 Keyboard [Logitech K400] on usb-0000:00:15.0-2:2
[ 52.417924] input: Logitech M325 as /devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.2/0003:046D:C52B.000A/0003:046D:400A.000D/input/input22
[ 52.418176] logitech-hidpp-device 0003:046D:400A.000D: input,hidraw3: USB HID v1.11 Mouse [Logitech M325] on usb-0000:00:15.0-2:3
[ 52.817157] i2c_hid i2c-ELAN0630:00: i2c_hid_get_input: incomplete report (14/65535)
[ 60.934218] logitech-hidpp-device 0003:046D:400A.000D: HID++ 2.0 device connected.
[ 319.677829] kauditd_printk_skb: 15 callbacks suppressed
[ 319.677832] audit: type=1400 audit(1538217366.137:27): apparmor="DENIED" operation="open" profile="/usr/sbin/cups-browsed" name="/usr/local/lib/libgcrypt.so.20.2.2" pid=3054 comm="cups-browsed" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 319.679599] audit: type=1400 audit(1538217366.141:28): apparmor="DENIED" operation="open" profile="/usr/sbin/cups-browsed" name="/usr/local/lib/libgpg-error.so.0.22.0" pid=3054 comm="cups-browsed" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 517.984726] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

    description: Notebook
    product: 81A4 (LENOVO_MT_81A4_BU_idea_FM_ideapad 120S-11IAP)
    vendor: LENOVO
    version: Lenovo ideapad 120S-11IAP
    serial: YD033K9M
    width: 64 bits
    capabilities: smbios-3.0 dmi-3.0 vsyscall32
    configuration: administrator_password=enabled boot=normal chassis=notebook family=ideapad 120S-11IAP frontpanel_password=disabled keyboard_password=disabled power-on_password=disabled sku=LENOVO_MT_81A4_BU_idea_FM_ideapad 120S-11IAP uuid=EB696E64-DB11-1720-1012-184233000000
  *-core
       description: Motherboard
       product: LNVNB161216
       vendor: LENOVO
       physical id: 0
       version: SDK0J91216 WIN
       serial: YD033K9M
       slot: Part Component
     *-cache:0
          description: L1 cache
          physical id: 0
          slot: L1 Cache
          size: 24KiB
          capacity: 24KiB
          capabilities: synchronous internal write-back data
          configuration: level=1
     *-cache:1
          description: L1 cache
          physical id: 1
          slot: L1 Cache
          size: 32KiB
          capacity: 32KiB
          capabilities: synchronous internal write-back instruction
          configuration: level=1
     *-cache:2
          description: L2 cache
          physical id: 2
          slot: L2 Cache
          size: 1MiB
          capacity: 1MiB
          capabilities: synchronous internal write-back unified
          configuration: level=2
     *-cpu
          description: CPU
          product: Intel(R) Celeron(R) CPU N3350 @ 1.10GHz
          vendor: Intel Corp.
          physical id: 3
          bus info: cpu@0
          version: Intel(R) Celeron(R) CPU N3350 @ 1.10GHz
          serial: To Be Filled By O.E.M.
          slot: U3E1
          size: 1134MHz
          capacity: 2400MHz
          width: 64 bits
          clock: 100MHz
          capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology tsc_reliable nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg cx16 xtpr pdcm sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave rdrand lahf_lm 3dnowprefetch cpuid_fault cat_l2 ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust smep erms mpx rdt_a rdseed smap clflushopt intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts arch_capabilities cpufreq
          configuration: cores=2 enabledcores=2 threads=2
     *-memory
          description: System Memory
          physical id: 4
          slot: System board or motherboard
          size: 2GiB
        *-bank:0
             description: DIMM Synchronous 2133 MHz (0.5 ns)
             product: K4F8E304HB-MGCJ
             vendor: Samsung
             physical id: 0
             serial: 00000000
             slot: ChannelA-DIMM0
             size: 1GiB
             width: 8 bits
             clock: 2133MHz (0.5ns)
        *-bank:1
             description: DIMM Synchronous 2133 MHz (0.5 ns)
             product: K4F8E304HB-MGCJ
           ...

This ticket is from 2016. A fifo underrun is a clear problem. I can reproduce this easily with my external monitor.
What information do you need to look at this?

shaju@678:~$ dmesg | grep i915
[ 2.088602] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 2.103420] [drm] Initialized i915 1.6.0 20171023 for 0000:00:02.0 on minor 0
[ 2.264884] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[10947.862266] WARNING: CPU: 1 PID: 1174 at /build/linux-hwe-O570pP/linux-hwe-4.15.0/drivers/gpu/drm/i915/intel_display.c:1247 assert_plane+0x98/0xa0 [i915]
[10947.862307] nf_nat_ftp nf_nat binfmt_misc nf_conntrack_ftp nf_conntrack libcrc32c iptable_filter parport_pc ppdev ip_tables x_tables lp parport autofs4 ums_realtek hid_generic usbhid hid uas usb_storage i915 i2c_algo_bit drm_kms_helper psmouse syscopyarea sysfillrect sysimgblt fb_sys_fops wmi sky2 drm video
[10947.862365] RIP: 0010:assert_plane+0x98/0xa0 [i915]
[10947.862417] assert_planes_disabled.isra.96+0x4d/0x70 [i915]
[10947.862453] intel_disable_pipe+0x58/0x190 [i915]
[10947.862512] i9xx_crtc_disable+0x7e/0x410 [i915]
[10947.862549] intel_atomic_commit_tail+0x1f4/0xd90 [i915]
[10947.862585] intel_atomic_commit+0x282/0x2b0 [i915]
[10947.862673] intel_fbdev_set_par+0x1a/0x70 [i915]
[10947.880823] WARNING: CPU: 0 PID: 1174 at /build/linux-hwe-O570pP/linux-hwe-4.15.0/drivers/gpu/drm/i915/intel_display.c:1247 assert_plane+0x98/0xa0 [i915]
[10947.880864] nf_nat_ftp nf_nat binfmt_misc nf_conntrack_ftp nf_conntrack libcrc32c iptable_filter parport_pc ppdev ip_tables x_tables lp parport autofs4 ums_realtek hid_generic usbhid hid uas usb_storage i915 i2c_algo_bit drm_kms_helper psmouse syscopyarea sysfillrect sysimgblt fb_sys_fops wmi sky2 drm video
[10947.880921] RIP: 0010:assert_plane+0x98/0xa0 [i915]
[10947.880973] assert_planes_disabled.isra.96+0x4d/0x70 [i915]
[10947.881009] intel_enable_pipe+0x58/0x200 [i915]
[10947.881045] i9xx_crtc_enable+0x373/0x480 [i915]
[10947.881082] intel_update_crtc+0x47/0xa0 [i915]
[10947.881117] intel_update_crtcs+0x5d/0x70 [i915]
[10947.881153] intel_atomic_commit_tail+0x3ad/0xd90 [i915]
[10947.881189] intel_atomic_commit+0x282/0x2b0 [i915]
[10947.881288] intel_fbdev_set_par+0x1a/0x70 [i915]
[10947.900888] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[11015.563288] WARNING: CPU: 0 PID: 997 at /build/linux-hwe-O570pP/linux-hwe-4.15.0/drivers/gpu/drm/i915/intel_display.c:1247 assert_plane+0x98/0xa0 [i915]
[11015.563353] nf_nat_ftp nf_nat binfmt_misc nf_conntrack_ftp nf_conntrack libcrc32c iptable_filter parport_pc ppdev ip_tables x_tables lp parport autofs4 ums_realtek hid_generic usbhid hid uas usb_storage i915 i2c_algo_bit drm_kms_helper psmouse syscopyarea sysfillrect sysimgblt fb_sys_fops wmi sky2 drm video
[11015.563430] RIP: 0010:assert_plane+0x98/0xa0 [i915]
[11015.563497] assert_planes_disabled.isra.96+0x4d/0x70 [i915]
[11015.563542] intel_disable_pipe+0x58/0x190 [i915]
[11015.563613] i9xx_crtc_disable+0x7e/0x410 [i915]
[11015.563659] intel_atomic_commit_tail+0x1f4/0xd90 [i915]
[11015.563704] intel_atomic_commit+0x282/0x2b0 [i915]
[11015.588602] WARNING: CPU: 0 PID: 997 at /build/linux-hwe-O570pP/linux-hwe-4.15.0/drivers/gpu/drm/i915/intel_display.c:1247 assert_plane+0x98/0xa0 [i915]
[11015.588684] nf_nat_...

Hubert Hesse, to confirm this is resolved for you in Ubuntu, could you please either upgrade your 16.04 enablement stack as per https://wiki.ubuntu.com/Kernel/LTSEnablementStack or test http://cdimage.ubuntu.com/daily-live/current/ and advise to the results?

Still a problem in 18.04.1 with the latest HWE kernel.

Jan 11 10:33:02 sergey-tpd kernel: [ 54.881476] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
Jan 11 10:33:02 sergey-tpd kernel: [ 54.882306] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

Lenovo T570 Kubuntu 18.04.1

Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

Linux xxxx-xxx 4.18.0-13-generic #14~18.04.1-Ubuntu SMP Thu Dec 6 14:09:52 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Let me join this with the following `dmesg | tail`:

[Feb24 23:34] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 00:23] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 01:57] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 04:04] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 04:59] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 06:19] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 06:31] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Feb25 06:47] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

4.18.0-15-generic #16-Ubuntu SMP Thu Feb 7 10:56:39 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
on an i7-6700

The flickering and the system crashes are gone, but the error still persits in the logs.

complement (sorry for multiple-comments):

$ dmesg | grep i915
[ 1.439662] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 1.439938] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[ 1.443269] [drm] Initialized i915 1.6.0 20180514 for 0000:00:02.0 on minor 0
[ 1.523397] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 15.764955] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[56162.413053] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[59291.355801] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[64022.043888] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[68572.684020] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[84907.749926] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[131695.137832] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[140974.062510] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[152485.446459] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[155522.518586] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[164965.550908] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[165879.406055] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[178549.854547] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[185381.350517] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[187311.834886] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[188858.938318] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[195515.961747] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[195618.444271] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[206235.029303] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[217208.530378] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[222859.639505] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[225820.223051] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[231471.431276] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[239098.879129] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[242398.343295] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[247190.079036] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[247912.015060] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[248846.631100] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[258283.737675] [drm:intel_cpu_fifo_underrun_ir...

---------- Forwarded message ---------
From: 678 <email address hidden>
Date: Sat, Mar 2, 2019 at 10:11 AM
Subject: Re: [Bug 1550779] Re: [Lenovo ThinkPad X220] *ERROR* CPU pipe A
FIFO underrun - Xorg glitches
To: Bug 1550779 <email address hidden>

On 02/03/19 12:40 AM, Tom Mittelstaedt wrote:
> complement (sorry for multiple-comments):
>
>
> $ dmesg | grep i915
> [ 1.439662] i915 0000:00:02.0: vgaarb: changed VGA decodes:
olddecodes=io+mem,decodes=io+mem:owns=io+mem
> [ 1.439938] [drm] Finished loading DMC firmware
i915/skl_dmc_ver1_27.bin (v1.27)
> [ 1.443269] [drm] Initialized i915 1.6.0 20180514 for 0000:00:02.0 on
minor 0
> [ 1.523397] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
> [ 15.764955] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops
i915_audio_component_bind_ops [i915])
> [56162.413053] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [59291.355801] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [64022.043888] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [68572.684020] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [84907.749926] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [131695.137832] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [140974.062510] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [152485.446459] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [155522.518586] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [164965.550908] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [165879.406055] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [178549.854547] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [185381.350517] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [187311.834886] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [188858.938318] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [195515.961747] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [195618.444271] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [206235.029303] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [217208.530378] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [222859.639505] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [225820.223051] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [231471.431276] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [239098.879129] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
> [242398.343295] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
...

Certainly there is bug position which is continuing with my machine and
programe need attention..

On Sat, Mar 2, 2019 at 11:55 AM Shaju കോട്ടയം <email address hidden> wrote:

>
>
> ---------- Forwarded message ---------
> From: 678 <email address hidden>
> Date: Sat, Mar 2, 2019 at 10:11 AM
> Subject: Re: [Bug 1550779] Re: [Lenovo ThinkPad X220] *ERROR* CPU pipe A
> FIFO underrun - Xorg glitches
> To: Bug 1550779 <email address hidden>
>
>
>
> On 02/03/19 12:40 AM, Tom Mittelstaedt wrote:
> > complement (sorry for multiple-comments):
> >
> >
> > $ dmesg | grep i915
> > [ 1.439662] i915 0000:00:02.0: vgaarb: changed VGA decodes:
> olddecodes=io+mem,decodes=io+mem:owns=io+mem
> > [ 1.439938] [drm] Finished loading DMC firmware
> i915/skl_dmc_ver1_27.bin (v1.27)
> > [ 1.443269] [drm] Initialized i915 1.6.0 20180514 for 0000:00:02.0 on
> minor 0
> > [ 1.523397] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
> > [ 15.764955] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops
> i915_audio_component_bind_ops [i915])
> > [56162.413053] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [59291.355801] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [64022.043888] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [68572.684020] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [84907.749926] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [131695.137832] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [140974.062510] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [152485.446459] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [155522.518586] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [164965.550908] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [165879.406055] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [178549.854547] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [185381.350517] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [187311.834886] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [188858.938318] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [195515.961747] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [195618.444271] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [206235.029303] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [217208.530378] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [222859.639505] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe A FIFO underrun
> > [225820.223051] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERRO...

I suspect the Xorg modesetting driver's atomic logic might have something to do with this. Can someone experiencing the problem please try logging into 'Ubuntu on Wayland' and tell us if that avoids the issue?

I think this issue has been affecting me for a few years now but I just recently started to look into it.

My current system is Ubuntu 19.04 but this issue was present even when I was using 18.04 and 18.10 and even before that.

OS: Ubuntu 19.04
CPU: Intel Core i7 6700
Graphics (integrated only): HD Graphics 530 (Skylake GT2)

Anyway, from time to time only one of my monitors turn on. When that happens `dmesg | grep i915` prints this:

```
➜ ~ dmesg -e | grep i915
[ +0.000545] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ +0.000627] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[ +0.003052] [drm] Initialized i915 1.6.0 20181204 for 0000:00:02.0 on minor 0
[ +0.000036] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ +0.000047] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ +0.249846] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

➜ ~ dmesg -T | grep i915
[Sat Apr 27 17:47:08 2019] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[Sat Apr 27 17:47:08 2019] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[Sat Apr 27 17:47:09 2019] [drm] Initialized i915 1.6.0 20181204 for 0000:00:02.0 on minor 0
[Sat Apr 27 17:47:09 2019] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[Sat Apr 27 17:47:09 2019] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[Sat Apr 27 17:47:09 2019] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
```

When I switch to Wayland, sometimes none of my monitors turn on at all. Once when both turned on, I turned off one
and tried to turn it back on again, but it went into energy saving mode. Then `dmesg` was showing this:

```
➜ ~ dmesg -T | grep i915
[Sat Apr 27 18:14:17 2019] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[Sat Apr 27 18:14:17 2019] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[Sat Apr 27 18:14:18 2019] [drm] Initialized i915 1.6.0 20181204 for 0000:00:02.0 on minor 0
[Sat Apr 27 18:14:18 2019] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[Sat Apr 27 18:14:18 2019] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[Sat Apr 27 18:14:56 2019] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

➜ ~ dmesg -e | grep i915
[ +0.000664] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ +0.000861] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[ +0.016298] [drm] Initialized i915 1.6.0 20181204 for 0000:00:02.0 on minor 0
[ +0.000047] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ +0.000047] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ +23.689059] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

```

I have attached the complete dmesg output in case that might help.

Since I'm also facing this bug I just want to confirm that the error also occurs on the latest mainline Kernel (5.1) and also on the current drm-tip kernel version (5.1.0.0994 from https://kernel.ubuntu.com/~kernel-ppa/mainline/drm-tip/2019-05-05/)

I'm trying to use an additional monitor on my X380 Yoga using an USB-C Dock. During the boot process the error message appears:
[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO
After the boot process the monitor is sometimes enabled, but only a couple of seconds.

I'm facing this issue in the latest kernel mainline, too.
CPU is an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz (which uses i915 graphics).

The graphic glitches were gone after some kernel update but the error messages in dmesg remained.

If someone else has those issues with a USB-C Dock (Thunderbolt 3) I got rid of the issue by using the latest mainline Kernel:
 5.1.0-050100-generic #201905052130 SMP Mon May 6 01:32:59 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
and the following Kernel config settings (/etc/default/grub):

GRUB_CMDLINE_LINUX_DEFAULT=".... quiet splash intel_idle.max_cstate=4 i915.enable_psr=0 i915.enable_dc=0 i915.enable_fbc=0 i915.enable_dp_mst=0"

I just recently created another report (https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1848123).
So I'm using an HP 840 G5, connected with USB TypeC to Dock G4 which feeds two DP screens.
After each wake from S3 sleep, both displays are flickering and all the cores are clocked to 3,6GHz if I use the intel_pstate driver, the lid is closed. Only a cold boot helps this time.
I'll have a look on the Kernel parameters soon and update you.
BR

i915.enable_dp_mst=0 seems to disable one of the external monitors.
$ modinfo i915 | grep enable_dp_mst
parm: enable_dp_mst:Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true) (bool)

Yes disabling multi-stream transport makes it a single stream, hence it can only then drive a single monitor.

This time I've added 'i915.enable_psr=0 i915.enable_dc=0 i915.enable_fbc=0' to the kernel parameters. In the current session I had to manually reconnect the notebook to the docking station and after a few seconds, the displays came back to life. No flickering at all, it just took a little bit more time to came alive.
Previously I could manage the external displays to work this way, but these remain flickering even after 20 minutes.
But the CPU is clocked to 3.6GHz, kworker/0:1-kacpi_notify keep spiking the processor, I assume the lid open and close has triggered such action.
In the meanwhile set the ACPI module to debug mode and I can see these messages in the dmesg, seems to be some general purpose events but I couldn't find such (hex or dec) numeric ID in the linux/drivers/platform/x86

/trace_state), there are a lot of executions:
[ +0,000166] extrace-0141 ex_trace_point : Method Begin [0x000000003e97f7df:\_GPE._L69] execution.
[ +0,000003] extrace-0141 ex_trace_point : Method End [0x000000003e97f7df:\_GPE._L69] execution.
What could be this address? This system seems to laggy and the CPU is around 70 oC, normally it would be somewhere around 40-50 oC.

Regards

Just a small update:
I have been using i915.enable_psr=0 i915.enable_dc=0 i915.enable_fbc=0 i915.enable_dp_mst=1 parameters for a few days, but except the very first or first two days when I unplugged the docking station, it doesn't helped at all.
So I decided to add error_capture=1 (record the GPU state following a hang) and a few days later complete it with a manual/udev disable for the i915 rc6. The kernel parameter has been removed (https://bugzilla.redhat.com/show_bug.cgi?id=1573482), however the function is still in the driver (/sys/class/drm/card0/power/rc6_enable:1).

Regards

Whoops. We still have the functionality of rc6, just under a different name
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fb6db0f5bf1d4d3a4af6242e287fa795221ec5b8

Since my upgrade from 19.04 to 19.10 my T430 is facing a similar problem with i915 fifo underruns:

The problem occurs by switching from user A to B. If user A is logged in and want to switch to another user B (e.g. admin), then after entering the credentials of the user B, the system hangs up.

Sometimes the system does not hang up directly. In this case the lock screen pops up and if I try then to enter the credentials of user B again, then the system hangs up. If I enter the credentials of the former already logged in user A, then system does not hang up.

Do we have actually somebody assigned to this report? I've been playing with the module parameters but nothing seem to be helping.
I added the debug parameter today, because none of the i915.enable_hangcheck=1 i915.error_capture=1 i915.verbose_state_checks=1 were helpful.
Should I fill a bug report at Freedesktop?

Regards

there's a big rewrite of DP MST being done upstream

https://patchwork.freedesktop.org/series/68359/

which is the last portion of it. You could try latest drm-tip mainline build from the mainline ppa to see if it's any better now.

anyway, having 'fifo underrun' in dmesg can mean many things, and likely isn't the same cause for everyone on this bug, so I'm not sure it's useful to have a 3+ year old bug about it open. File a new bug if you still see it with the latest Ubuntu release and/or upstream kernel.

@tjaalton I find this bug report useful since I can receive updates on how the situation evolves. If there are know separate subclasses of the issue which are fixed separately I agree that it would be a good idea to provide debugging steps here to classify each subclass and track the subclass as a separate bug.
When the error in the title fully goes away, the bug can be closed.

Hi Timo,

I wanted to try the AMD64 version at: https://kernel.ubuntu.com/~kernel-ppa/mainline/drm-tip/2019-11-14/.
But only unsigned kernels are shipped and I couldn't switch from UEFI or boot unsigned kernels, because it's a corporate machine.
Do you have any ideas?

Regards

@tjaalton?

It looks the same bug on my Linux Mint 19.2 Cinnamon, Linux Kernel: 4.15.0-72-generic
Using second second monitor with NVIDIA Corporation GF108M [GeForce GT 525M] graphics.
The error log is on tty1 console:
    [drm:intel_set_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
    [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A

Hello,

I think I am experiencing the same issue so I am not opening a new bug report. Below is the description I also posted a question about:

I have upgraded to Kubuntu 20.04 from 19.10. Session went ok but after rebooting I noticed one or two times where my screen (external monitor connected via display port to my laptop) went on and off for 1-2 seconds. After the recent update to Kernel 5.4.0-40 and then to 5.4.0-42 these on and off instances are more frequent. System and sound etc works (doesn't hang) , only the screen goes black and on again, which is very annoying. This does not happen with HDMI cable connected, but instead there are some minor screen glitches, not very often though. I did not have any of those with 19.10...my system is details are shown below:. See especially the last part ie dmesg | grep -i i915.

Note that reverting to kernel 5.4.0-39 things go back to normal.

Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.4.0-40-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i5-10210U CPU @ 1.60GHz
Memory: 15,5 GiB of RAM

lspci

00:00.0 Host bridge: Intel Corporation Device 9b61 (rev 0c)
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics (rev 02)
00:12.0 Signal processing controller: Intel Corporation Comet Lake Thermal Subsytem
00:14.0 USB controller: Intel Corporation Device 02ed
00:14.2 RAM memory: Intel Corporation Device 02ef
00:15.0 Serial bus controller [0c80]: Intel Corporation Serial IO I2C Host Controller
00:16.0 Communication controller: Intel Corporation Comet Lake Management Engine Interface
00:17.0 SATA controller: Intel Corporation Comet Lake SATA AHCI Controller
00:1c.0 PCI bridge: Intel Corporation Device 02bc (rev f0)
00:1d.0 PCI bridge: Intel Corporation Device 02b0 (rev f0)
00:1d.1 PCI bridge: Intel Corporation Device 02b1 (rev f0)
00:1d.4 PCI bridge: Intel Corporation Device 02b4 (rev f0)
00:1f.0 ISA bridge: Intel Corporation Device 0284
00:1f.3 Audio device: Intel Corporation Device 02c8
00:1f.4 SMBus: Intel Corporation Device 02a3
00:1f.5 Serial bus controller [0c80]: Intel Corporation Comet Lake SPI (flash) Controller
01:00.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3 Bridge [Titan Ridge 2C 2018] (rev 06)
02:00.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3 Bridge [Titan Ridge 2C 2018] (rev 06)
02:01.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3 Bridge [Titan Ridge 2C 2018] (rev 06)
02:02.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3 Bridge [Titan Ridge 2C 2018] (rev 06)
03:00.0 System peripheral: Intel Corporation JHL7540 Thunderbolt 3 NHI [Titan Ridge 2C 2018] (rev 06)
3a:00.0 USB controller: Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 2C 2018] (rev 06)
3b:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTL8411B PCI Express Card Reader (rev 01)
3b:00.1 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 12)
40:00.0 Network controller: Intel Corporation Wi-Fi 6 AX200 (rev 1a)
45:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981

inxi ...

I suspect the Xorg modesetting driver's atomic logic might have something to do with this. Can someone experiencing the problem please try logging into 'Ubuntu on Wayland' and tell us if that avoids the issue?

I initially saw flickering with Wayland, so i switched to Xorg to check if it happens also there... and it happens.

I feel like it's happening when i move my mouse close to the bottom of the screen and when using Firefox Nightly. Though I might be imagining patterns or becoming crazy.

... That said, it seems that the issues are mostly if not allways happening when the mouse is not moving (whether at the bottom or not according my previous post, usually, if not always somewhere close to bottom of screen).
But when i move the mouse while the blinkings happen they stop.