[nouveau] External monitor plugged into (secondary) Nvidia GPU is all white (plus a little flicker)

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Maybe this was caused by an Ubuntu config change? Building 5.14.20 and 5.14.1 from git results in failure now. Only the mainline debs of those versions succeed.

Just wanted to chime in and say I am having the same issue on my Lenovo P1 which has both Intel and Nvidia cards. Ubuntu 21.10 worked flawlessly, 22.04 displays a pure white screen on my external display.

For a variety of reasons, we don't recommend anyone use the default nouveau driver. I only opened this bug for the sake of tracking. Please open the 'Additional Drivers' app and install the proprietary Nvidia driver instead.

I think what you are saying is that nouveau is not maintained by Ubuntu. I am just curious if Ubuntu made a config changed that caused this issue, or if it was an update to nouveau itself. I personally like nouveau because it allows automatic graphics switching, and the last time I tried the native Nvidia drivers, it ate a lot of battery.

The change that caused this bug is the newer kernel in Ubuntu 22.04. Not anything we did directly to affect nouveau, we just seem to have inherited a new nouveau bug. Older kernels do not have the bug.

Another DRM regression in v5.14.21: bug 1971146

We should check to see if this is the cause:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1971146/comments/29

should be easy to test with 'intel_iommu=off' on the kernel cmdline

Yes! Fixed by intel_iommu=off

There's dmar error, i thought Device[01:00.0] may access a out-of-bound address.
[ 843.730480] DMAR: DRHD: handling fault status reg 3
[ 843.730488] DMAR: [DMA Read NO_PASID] Request device [01:00.0] fault addr 0x6e000000 [fault reason 0x0c] non-zero reserved fields in PTE
[ 843.730494] DMAR: DRHD: handling fault status reg 3
[ 843.730496] DMAR: [DMA Read NO_PASID] Request device [01:00.0] fault addr 0x6e016000 [fault reason 0x0c] non-zero reserved fields in PTE
[ 843.730499] DMAR: DRHD: handling fault status reg 3
[ 843.730501] DMAR: [DMA Read NO_PASID] Request device [01:00.0] fault addr 0x6e01e000 [fault reason 0x0c] non-zero reserved fields in PTE
[ 843.730505] DMAR: DRHD: handling fault status reg 3

Could someone dump
sudo cat /sys/bus/pci/devices/0000\:01\:00.0/iommu/intel-iommu/*
sudo cat /sys/bus/pci/devices/0000\:01\:00.0/iommu_group/reserved_regions
sudo cat /sys/bus/pci/devices/0000\:01\:00.0/iommu_group/type

could someone help to verify this kernel on target w/o intel_iommu=off?thanks
https://drive.google.com/drive/folders/1c1p8y265T9urgOwKoJLXaiGUrlKpJlKO?usp=sharing

Can you upload it to a more familiar/trustworthy URL?

Confirmed that test kernel 5.14.0-1033lpv1967153-oem does not have the bug. Even without intel_iommu=off.

Fix released in jammy https://launchpad.net/ubuntu/+source/linux/5.15.0-40.43 according to bug 1971699.

Verified fixed in 5.15.0-40-generic

Although my nouveau setup is seemingly less reliable than it used to be, there is no white screen and I eventually got a working signal from the Nvidia card.

intel_iommu=off may result in a security risk as PCIe devices can access all of the RAM. intel_iommu=igfx_off should be enough to resolve issues with GPUs.

Verified:

FAIL: intel_iommu=on
PASS: intel_iommu=off
PASS: intel_iommu=igfx_off
PASS: No parameter required in 5.15.0-40-generic

Please test the kernel, which adds the affected GFX to IOMMU quirk list:
https://people.canonical.com/~khfeng/gfx-no-dmar/

See also bug 2006370

Comment number three [driver update to tested] provides error (see the screenshot)
This window with the error cannot be closed (bug); I tried everything, including pressing close the window button.

intel_iommu=igfx_off - not helped (input goes OK, but the bug is still here)

Suggested solution:
https://people.canonical.com/~khfeng/gfx-no-dmar/
=>
linux-modules-extra-5.15.0-1050-generic_5.15.0-1050.56_amd64.deb
Error with no description (screenshot attached)

PS: The second attempt to follow to the comment number three: Error with no description (see the screenshot)
It then automatically selects the last option (no other option end with success).

My kernel is: 5.19.0-35-generic

Hi everyone,
It seems my bug is unsolvable. I will hope for a better Linux (Ubuntu) version since no other choices exist.
This bug makes me a very rare Linux user (I can't work on just one monitor).
So, Happy Easter Everyone!
Best Wishes,
Alex.

This bug is solved. The above comments probably belong in bug 2006370, not here.

Ubuntu 22.10 (Kinetic Kudu) has reached end of life, so this bug will not be fixed for that specific release.