log out or switch user results in crash

I can confirm the black screen (not the freezing system) upon log-out and switch user behaviour - a few days ago... but strangely, that behaviour vanished again after a lot of messing around with my fglrx settings and attempt to get my ati radeon xpress 200m to run with desktop effects or compiz (not succeeded).

I found to my horror that this 'black screen on log-off/switch user' issue has been replaced by 'hibernation not working' !! Too bad, because I used hibernation more than log-off/switch user :(

Thanks for taking the time to report this bug and helping to make Ubuntu better. This bug has been filed against the linux-restricted-mules-2.6.8.1 but I supect that isn't really what you wanted. What kernel version are you using? Thanks in advance.

Linux xombie1 2.6.20-15-generic #2 SMP Sun Apr 15 07:36:31 UTC 2007 i686 GNU/Linux

Sorry I forgot when I posted.

Ok, here's an update: I reported earlier that this behaviour had somehow vanished from my system...

Well, it's back again! Trying to fix an issue with hibernation, I found out that my install was not using swap at all. After restoring system swapping again, the issue with system lock-up/black screen after Switch User / Log off haunts me once more :(

Thinking back, the issue disapeared around the time I was messing with /etc/fstab settings (because of fsck running each boot-up) which mostl likely caused my swap partition to become 'out of use'...

Any conclusions that van be derived from this?

I am running kernel version 2.6.20-15-generic (Feisty 64bit) on an AMD64 machine.

I am also experiencing this problem on a clean install of Feisty AMD64 with the latest fglrx. Please let me if you need any information from me.

I can confirm the black screen on log out using the resricted driver with an ati radeon xpress 200m.

Editing /etc/X11/gdm/gdm.conf so AlwaysRestartServer=true is a valid workaround. I cannot speak to issues with hibernation but can also second the fact that this is a bug that was introduced some time during the Feisty beta, as logging out did work once without a workaround.

For what it's worth, I suggest this is an important bug, as the ati radeon xpress 200m is an all too common card and the problem a real show-stopper.

Sadly, /etc/X11/gdm/gdm.conf > AlwaysRestartServer=true doesn't fix it on my machine (feisty 64bit/radeon xpress 200m)...

Does not work for me either Feisty 7.04 radeon xpress 200 card.

There does seem to be a lot of people have a lot of problems with this card in the breif time i have been looking through the forums.

I also tried this fix and it did not work for me.

I am using Ubuntu 7.04 with kernel 2.6.20-15-generic

My Laptop is an Acer 5100 with ATI Radeon Xpress 1100 graphics

I was able to log in and out with no problems up till this day (I only installed Ubuntu a few days ago)

The fix suggested above did not work for me either.

I am using using Ubuntu 7.04 with kernel 2.6.20-15-generic as well.

My video card is a GeForce FX 5200

This install was from the 7.04 Beta.

I have a clean install of feisty 7.04 final on with nvidia GeForce 6200 card utilizing nvidia driver from restricted drivers manager. (In other words a very stock installation). This bug really detracts from the waf of feisty. The switch user feature worked fine on this system in edgy and dapper.

To be more precise in my bug report:

kernel: 2.6.20-15-generic

nvidia-glx: 1:1.0.9631+2.6.20.5-15.20

The AlwaysRestartServer fix had no effect on this error for me.

STEPS TO RECREATE BUG

1. log in to user 1
2 select switch user
3. log in to user 2
4. log off user 2
Black Screen

VARIATION ON CREATING BUG AND 2 EXTRA STEPS TO MAKE THINGS EVEN MORE ANNOYING
1. log in to user 1
2. switch user
3. log in to user 2
4. switch user
5. log in to user 1
black screen
...the plot thickens
a. ctrl-alt-bsp
b. log in to user 2
c. gdmgreeter plays bongos continuously
d. I jump from window (luckily I'm on the first floor)

I have solved my problem by disabling desktop effects. I had really started to like "the cube"

disabling desktop effects seems to have solved the problem for me as well. Should this be filed against desktop effects?

I do not have desktop effects enabled and have the problem.

On 4/24/07, muj0 <email address hidden> wrote:
>
> disabling desktop effects seems to have solved the problem for me as
> well. Should this be filed against desktop effects?
>
> --
> log out or switch user results in crash
> https://bugs.launchpad.net/bugs/107115
> You received this bug notification because you are a direct subscriber
> of the bug.
>

I have had this problem on my toshiba A135-S2386 laptop with an 200m ATI video card and the fglrx driver. I implemented the above fix and it has not reoccurred!

same problem here (black window when switching users)
Feisty with kernel 2.6.20-15-386, GeForce 4 MX 440 with nvidia driver 1.0-9631

AlwaysRestartServer=true does not fix it.

me too, it also occurs when swichting to say tty4 and then trying to switch back to tty7
Feisty @ 2.6.20-15-generic i686
GeForce Go 6800 Ultra
nvidia driver
in most cases i can still see my mouse pointer

workarounds:
- sometimes pressing ctrl+alt+l, pressing a key, entering my password and pressing enter brings up my desktop again (does not always work)
- without beryl active, there's no more black screens (for me)

I seem to be having a similar problem. This happens only when I'm using fglrx (doesn't happen with radeon [ati] driver). This problem is occuring with newest drivers downloaded from ATI, and also the restricted-modules package.

Kubuntu 7.04 using 2.6.20-15-generic
HP nx6125 Laptop
Turion64 2GHz
ATI xpress 200m (128MB shared, set in BIOS).

Please let me know if there is any information I can give you or help you verify.

I have a G_Force 5800 and Desktop effects are disabled. Same problem here. Running Fiesty Fawn 2.6.20-15-386 (#2. I haven't tried zerv's workaround yet but I will shortly.

>workarounds:
>- sometimes pressing ctrl+alt+l, pressing a key, entering my password and pressing enter brings up my desktop again (does not always work)
>- without beryl active, there's no more black screens (for me)

Well I tried to recreate the problem with Beryl active and whala. Everything works as expected.
Note: My Beryl installation is above the desktop effects. Could this if fact be the problem? Do you also have Beryl installed as a second application?

I have the same problem. Whenever I try to get back to an existing system, my graphics go out. I can tell that the system is still active, I just can't see anything and the screen goes haywire. If I type my password and hit enter, even though the screen is blank, I can tell that the system logs me in. CTL+ALT+BACKSPACE does not fix the problem for me, nor does setting the RESTART XSESSION to true.

I posted a separate bug on this issue before I knew about this one: https://bugs.launchpad.net/ubuntu/+bug/109357

There is also another forum thread on the matter here: http://ubuntuforums.org/showthread.php?p=2517231

nvidia users with this issue should see Bug #88152 ...

I have this with a new Kubuntu Feisty install with an ATI Mobility Radeon X300, 2.6.20-15-generic. I installed the latest ATI 8.36.5 with a manual build. I do not have beryl installed. Logging off a session (except a full restart), suspend, and hibernate are affected. I seem to be able to start a new session and switch users okay, so long as I don't log any of them off.

During one log off black-out, I saw the following on one of the screens, in case it helps...
  [1757.404000] [fglrx:firegl_mmap] *ERROR* No map found!
  [1757.404000] [fglrx:firegl_unlock] *ERROR* Process 5907 using kernel context 0

One other oddity in case it's related. If I start a new session, the second one goes onto vt9 instead of vt8. vt8 shows console text:
* Checking battery state... [OK ]
Starting K Display Manager: kdm.
* Running local boot scripts (/etc/rc.local) [ OK ]

I had the problem before upgrading from Edgy and hoped it would go away with Feisty. I first noticed it when I upgraded the ATI driver in Edgy. As of right now, it goes away if I disable the restricted driver. I haven't tried anything else to fix it. I do notice that if I hit ctrl-alt-backspace, I am able to log in again.

I have this problem also, I'm using restricted driver fglrx with Radeon Xpress 200M on a Compaq Presario v5000 series laptop, fglrxinfo gives the following info

OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: RADEON XPRESS Series
OpenGL version string: 2.0.6334 (8.34.8)

When I logout, hibernate, susbend, the system blacks out after processing my request, I can tell that the computer is still operating normally, it's just not displaying any information.
When I try to get around it by checking "Restart Xserver with each login", the logout sometimes shows the login panel, however, if I type in my user/pass, the system hangs again.
I hope this confirms the bug. Thank you.

Editing /etc/X11/gdm/gdm.conf and setting AlwaysRestartServer to true works for me

I have an HP NX6125 laptop with Ati Radeon Xpress 200M chipset.

fglrxinfo output:
  display: :0.0 screen: 0
  OpenGL vendor string: ATI Technologies Inc.
  OpenGL renderer string: RADEON XPRESS Series
  OpenGL version string: 2.0.6334 (8.34.8)

New fglrx driver 8.37.6 fix problem.

fglrx 8.37.6 changelog:
Logging out of a session to the graphical login manager no longer crashes the Xserver

Driver fglrx 8.37.6 NOT FIX PROBLEM.

My computer hang always when I change user

Is there an equivalent setting to the "AlwaysRestartServer" in KDM?

The equivalent modifications to KDM are:
1. Open /etc/kde3/kdm/kdmrc
2. Search for & uncomment the line "TerminateServer=True" (or just add this line, if there is no comment).

This worked for me on 32-bit Kubuntu Feisty, with Radeon Xpress200M Graphics Chipset (on a Compaq V2000Z, for anyone who cares).

I too get a black screen when I try to log out or switch user on my compaq V5000 laptop with an ati Ati Radeon Xpress 200M chipset.
Feisty 7.04, kernel 2.6.20-16 generic
Not using desktop effects
fglrxinfo
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: RADEON XPRESS Series
OpenGL version string: 2.0.6334 (8.34.8)

AlwaysRestartServer=true does not fix it

i to had this problem. however i can confirm that the above workaround does the trick. im using ubuntu studio 7.04. ati radeon xpress 200 chipset (desktop) here. as for the people who this isnt working for be sure to remove the "#" from the beginning of the line. where it says #AlwaysRestartServer=off should be changed to AlwaysRestartServer=true. also besure its like that in tall of the following files:

factory-gdm.conf
gdm.conf
gdm.conf-custom
gdm-cdd.conf

not everyone will have to change all 4 files but in my case i had to.

you will have to do (from terminal) sudo gedit /etc/X11/gdm/"filename here" to change each one though. hope this helps those still having a problem.

vax_fortran said
>The equivalent modifications to KDM are:
>1. Open /etc/kde3/kdm/kdmrc
>2. Search for & uncomment the line "TerminateServer=True" (or just add this line, if there is no comment).

>This worked for me on 32-bit Kubuntu Feisty, with Radeon Xpress200M Graphics Chipset (on a Compaq V2000Z, for anyone who cares).

I tried adding this to the General section of kdmrc - seems to have no effect on the problem. Is that the correct section, and any other suggestions re KDE?

Also, the lockup has been occurring when I attempt to shutdown as well as merely log out.

I have similar but diferent bug.

With driver "fglrx" or "ati" and AlwaysRestartServer=true hang.

Someone have the same problem with both drivers??

My bug: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/119635

I've packaged the fglrx driver, and put the debs up for testing on Gutsy (linux-restricted-modules-2.6.22):

    http://people.ubuntu.com/~bryce/Testing/

Among the changes in this newer fglrx are fixes for freezes when logging out or switching users, and when switching to a console (e.g., ctrl-alt-F1). I don't know if it fixes the hibernation not working issue that ravanhagen reports.
tasadar_f said he had tried 8.37.6 already and found it did not fix this issue, so I would appreciate feedback from others if this fixes it for them.

These are the packages I installed in my tests: fglrx-control, xorg-driver-fglrx, fglrx-kernel-source, linux-restricted-modules-common, linux-restricted-modules-2.6.22

Also turn off Composite if you have it on (fglrx doesn't support it)
fglrxinfo and glxgears are useful to verify its working

Not only do we get the "black screen of death" - the system hangs indefinetly - forcing us to power off our machines.

Where is the fix?

display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: RADEON XPRESS Series
OpenGL version string: 2.0.6334 (8.34.8)

ATI Radeon Xpress 200m

I too had this same problem.
Upon Log Out / Switch User (hybernation/suspend not tested), screen would go black and graphics would not come back. Only way out of it was manual shutdown.

I have a 200m:
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: RADEON XPRESS Series
OpenGL version string: 2.0.6334 (8.34.8)

kernel: 2.6.20-16-generic

I fixed this bug by setting AlwaysRestartServer=true on **both** of:

factory-gdm.conf
gdm.conf

Thanks! I fixed this with this setting as well !!

On 6/21/07, dOA <email address hidden> wrote:
>
> I too had this same problem.
> Upon Log Out / Switch User (hybernation/suspend not tested), screen would
> go black and graphics would not come back. Only way out of it was manual
> shutdown.
>
> I have a 200m:
> display: :0.0 screen: 0
> OpenGL vendor string: ATI Technologies Inc.
> OpenGL renderer string: RADEON XPRESS Series
> OpenGL version string: 2.0.6334 (8.34.8)
>
> kernel: 2.6.20-16-generic
>
> I fixed this bug by setting AlwaysRestartServer=true on **both** of:
>
> factory-gdm.conf
> gdm.conf
>
> --
> log out or switch user results in crash
> https://bugs.launchpad.net/bugs/107115
> You received this bug notification because you are a direct subscriber
> of the bug.
>

just a small update here. i did have it solved using the AlwaysRestartServer=true as stated earlier. however it didnt last long. but on the brighter site. the solution bryce posted works flawlessly. i used that solution myself. tried every thing i could think of to get x to crash (just as a test). had 5 videos going in each of 3 user accounts. as well as a pps2 gamme demmo running through an emulator inside of wine on each one.. continuosly switched between each account ever few minutes for about an hour. nothing would crash it. although this is a great solution it does take some work if your running fiesty like i am. you need to edit your sources list and change each "fiesty" entry to "gutsy". download the files bryce mentioned in his post from the link. then update the kernel before applying the updates mentioned (at least this is how i have done it). you of course can redit your sorce list back to fiesty after all this is done. another plus to all this is that the updated kernel seems much improved. at least on my pc boot up is at least 10 secs shorter. login about 2-3 secs shorter. as well as increased responsiveness.

@ Bryce Harrington (sorry, don't know how else to contact you directly)
I'd like to help test your packages, but as a newby i'm not sure how. I'm running Feisty 64bit. Can you advise me?

I have the same problem. Running Feisty (kernel: 2.6.20-16-generic). Have never got desktop effects to work (due to using Radeon x1600) - so I don't believe this to be the issue.

fixes built against a fiesty invironment are up.

http://people.ubuntu.com/~bryce/Testing/fglrx-8.37.6-Feisty/

work flawlessly for me. i used fglrx-control, xorg-driver-fglrx, fglrx-kernel-source, linux-restricted-modules-common,
linux-restricted-modules-2.6.16. all in 386,generic and lowlatency flavors. no issues here as of yet. 3d performance even seems better than the previous driver. and user switching,logout,suspend and hibrination all work for me. you have to d/l them from the above link though as the fiesty debs will not get put in the repos. be sure to pass the word. credit goes to bryce harrington. thankx bro:)

edit from above: 2.6.20 not 2.6.16

This bug was fixed in newer versions of fglrx, which is now available
in Gutsy.

There are no plans to add fglrx 8.37.6 to Feisty officially, but I've
created .debs for Feisty users needing this fix. These are available
at http://people.ubuntu.com/~bryce/Testing/fglrx-8.37.6-Feisty/.
Despite being unofficial, please feel welcome to report new bugs with
these packages to launchpad.

Please help spread word and help fellow users in installing it!

Any chance this can be made to work for 64bit Feisty?

Tried 8.37.6 on Feisty/KDE using bryce's packages - no change in the problem. Logging out or attempting a shutdown/restart always results in a frozen screen of garbage. I guess I'll hold my breath and wait for ATI to test their junk drivers on their hardware.

Bryce's updates did not work for me as well.

I have this (really annoying) problem. When I log off, the box just hanged with a blank screen. Ctrl+Alt+Backspace, Ctrl+Alt+Delete OR Ctrl+Alt+F1(F2-7) don't work at all. Had to hard-reboot the box.

Release: Dapper 6.06.1 LTS
Uname: Linux firestorm 2.6.15-28-686 #1 SMP PREEMPT Thu May 10 09:56:30 UTC 2007 i686 GNU/Linux
Fglrx: OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: MOBILITY RADEON X600 Generic
OpenGL version string: 2.0.5814 (8.25.18)

Note: I do NOT have beryl or compiz installed. Just plain good ol' Dapper. Also, workaround(s) does NOT work. *sigh*

to those who these new files havent worked for just a same tip. i have to uncheck the box under the restriceted manager. reboot. then use synaptic to remove the restricted modules (including common). remove fglrx control. fglrx kernel source. (cant remember if the fglrx driver and dev files was still there or not but id remove them too) using the complete removal option. reboot again. then install all the files/modules (fglrx control ,fglrx kernel source, linux restricted modules including common, xorg driver fglrx as well as dev). at least this is how i had to do it. also be sure you get the modules for your specific kernel (although im sure you already knew that). after all files are installed make sure the box is ticked under the restricted manager and reboot one final time. also as a side note while installing these files you will get a warning that another version is available in the software channel. be sure to ignore this warning and continue the install anyway (software channel versions are the old ones). hope this helps those that have yet to get the new drivers working. i have radeon xpress 200 graphics and they work great for me.

jeff vehrs: im almost certain that you problem is due to an old driver. those are the exact same problems i had befpre updating. however these modules are not build for a dapper environment. you could try getting the new kernel from the fiesty repos and give it a go (you will still need to get the models from the link given farther up). however as im rather new to ubuntu and linux in general im not sure if using a fiesty kernel on dapper would break anything or not.

After a lot of messing around I was finally able to fix this problem so I thought I'd share my solution. The AlwaysRestartServer patch didn't work for me so I tried installing the newest drivers (8.37.6) which I got from ATI's website. The drivers installed correctly but when I looked at dmesg it seemed like ubuntu kept loading the wrong version at startup. After a lot of searching I found the solution here:
https://help.ubuntu.com/community/BinaryDriverHowto/ATI
In order to successfully replace the drivers you have to follow this rather complicated procedure which involves installing some extra helper packages, hand-tweaking some config files and other linux kernel voodoo. Unless you're a supreme linux guru you'll need those instructions.

Reopening due to reports of the fglrx 8.37.6 not fixing it for some people.

Following instructions on https://help.ubuntu.com/community/BinaryDriverHowto/ATI#head-99489608eb537a1a0346cdd3ad34209d7887714a (for Feisty) I installed the latest ATI driver 8.39.4 (for Radeon Xpress 200M) and this bug/problem seems no longer there... Only a frozen mouse cursor but that's maybe related to my synaptic-touchpad driver?

> Following instructions on https://help.ubuntu.com/community/BinaryDriverHowto/ATI#head-99489608eb537a1a0346cdd3ad34209d7887714a (for Feisty) I installed the latest ATI driver 8.39.4 (for Radeon Xpress 200M) and this bug/problem seems no longer there... Only a frozen mouse cursor but that's maybe related to my synaptic-touchpad driver?

In testing 8.39.4 on Kubuntu Fiesty, I discovered that the log-out problem is not present if the S-Video cable is not attached at boot. If I attach a TV to S-Video at boot, I cannot log out or shut down normally (even if the cable is later disconnected). This may have been the case with earlier drivers as well.

If I try to log out or shut down with S-Video connected at boot, I get a black screen with just a mouse cursor for about 15 seconds, then it freezes with a screen full of gray and black garbage - same as earlier versions of the driver. Only way to avoid this is to Ctrl-Alt-F1, login as root, and "poweroff". (Once I press Ctrl-Alt-F1, I cannot return to KDE with Ctrl-Alt-F7 - freezes.)

The Synaptic Touchpad is working normally with 8.39.4. I'm using an HP NX6125 notebook.

Here is my device section, FWIW. Suggestions welcome.

Section "Device"
 Identifier "ATI Technologies Inc ATI Radeon XPRESS 200M 5955 (PCIE)"
 Driver "fglrx"
 Busid "PCI:1:5:0"
 Option "VideoOverlay" "on"
 Option "OpenGLOverlay" "off"
 Option "DesktopSetup" "clone"
 Option "OverlayOnCRTC2" "0"
EndSection

> Only a frozen mouse cursor but that's maybe related to my synaptic-touchpad driver?

I also have the frozen mouse cursor on my Gutsy Beta (amd64, using the fglrx driver provided by the third party driver dialogue, all updates until Oct. 6th) when I switch to a second user. I can unlock the mouse by switching back to the first user moving the mouse there, and then switching to the second. My video card is an "ATI Technologies Inc RS485 [Radeon Xpress 1100 IGP]". No idea, if it is related to the synaptic driver...

Oh, just enabled xserver-xgl and compiz which made the locking mouse cursor behaviour disappear.

Any update on this? Using Gutsy and ATI drivers... If Compiz is on, and I try switch user, I get the black screen and only thing I can do is a hard computer restart!

Thanks

I have a similar problem on Gutsy and only a hard computer restart helps. I get a black screen when either switching users or logging out! I thought this was due to CompizFusion, but even with CompizFusion disabled I get the black screen.

Is there any progress on this??
I have same problem except... every time i try to switch user...pc freezes and hard reset is only to boot.

I have Kubuntu 7.10, latest ati fglrx...
This same problem started w/ feisty so hopefully this will get fixed. Since feisty i have fresh installed my kubuntu twice.

If anyone needs any logs or so... i'll check or attach them.

i can confirm this bug with ubuntu 7.10 gutsy and ATI fglrx-driver. I have a pentium 4 system with an ATI Radeon 9600.
Disabling Desktop-Effects, CompizFusion or the above fixes didn't work for me.
Still get a Black Screen after Logout/Switch User and can only do a reset. (Ctrl-Alt-Backspace/Ctrl-Alt-F1 doesn't work)
Changing driver to "ati"/"radeon" in /etc/X11/xorg.conf fixes it, so it must be fglrx.

fglrxinfo prints this:
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: ATI RADEON 9600 Series
OpenGL version string: 2.0.6473 (8.37.6)

my kernel-version is:
Linux 2.6.22-14-generic with GNOME 2.20.1

Hope somebody can fix this.

This is a real show stopper for me. I really hope this gets fixed soon.

Confirming on 7.10, ATI fglrx driver. I also have a pentium 4 system with a Radeon 9600.

Confirming this issue on Gutsy Gibbon with FGLRX 8.02 (released 13th Feb 08). Running with KDM, so I've tried with the following remedies (which did not do it for me):
 * TerminateServer=true in kdmrc
 * Option "AGPMask" "0x00000005" # Disable 1x and 4x
 * Option "UseInternalAGPGART" "no"

However, I _am_ able to shift to console mode using Ctrl-Alt-Fx and back to X with no problems, but log outs and Ctrl-Alt-Backspace freezes the machine so that Caps Lock/Num Lock no longer can be toggled - but SysRq works.

This is what is present in the log file up to the point of the freeze:
Feb 15 09:35:57 nc6000 kernel: [fglrx] interrupt source 10000000 successfully disabled!
Feb 15 09:35:57 nc6000 kernel: [fglrx] enable ID = 0x00000000
Feb 15 09:35:57 nc6000 kernel: [fglrx] Receive disable interrupt message with irqEnableMask: 10000000; dwIRQEnableId: 00000005
Feb 15 09:35:57 nc6000 kernel: [fglrx] interrupt source 20008000 successfully disabled!
Feb 15 09:35:57 nc6000 kernel: [fglrx] enable ID = 0x00000000
Feb 15 09:35:57 nc6000 kernel: [fglrx] Receive disable interrupt message with irqEnableMask: 20008000; dwIRQEnableId: 00000004
Feb 15 09:36:29 nc6000 kernel: SysRq : Emergency Sync
Feb 15 09:36:29 nc6000 kernel: Emergency Sync complete

Also on Gutsy with the newest fglrx, but I can now log out and back
in, as well as switch to a console.

I was experiencing this problem with an ATI X700 on Kubuntu 7.10 with fglrx driver.
I tried the solution explained in http://ubuntuforums.org/showpost.php?p=4300658&postcount=3
It works well for me now.
So try the following :

sudo /usr/sbin/update-rc.d -f atieventsd remove

Newest fglrx and disabling composite extension fixed it for me.

I'm experiencing this on Hardy Heron beta. fglrx (ATI) + compiz.

I haven't tried many options to fix it.

I can however log out, and log in as a new user.

Jeff

I can confirm this too, on Hardy Heron 8.04 beta with latest drivers from the ATI website. Occasionally, logging out after switching user will lead to a black screen and a complete system hardlock.

I have the same problem with a nvidia card (7300 LE), the problem is the same but instead of a black screen I get a white one. If I disable desktop efects from both user it works fine otherwise not. Even though a white screen shows when switching users you can type your password and enter and you will be able to login, but it is not what all we want, is it?

I hope my version of the problem can help solving the entire problem.

Thanks in advance.

I have this problem as well on Gusty (64 bit) on my PC but it has the message of shutting down eth0 and hard locks the system and as well with hardy on my PS3 which there it hardlocks after hitting enter after the message it gives when it ejects the optical disk.

Complementing...

If I have to disable desktop efects, there is no point to have them on my pc...but they are very nice and we get used to them very fast!

I have had the same problem for a long time: every 10th switch crashed the system.
Crashes How badly ? blank screen + Numlock does not change the light on the keyboard (i.e. complete system stuck).
On Hardy Heron 8.04: it does this now most of the time. Hardy is the worst Ubumtu release I've seen so far.

My sysytem: Compaq dualcore, 2Gb memory with ATI card, using proprietary driver. (I don't see a tool anymore under system/administration with which I can provide more information)

I feel like I should open a new bug report, as my symptoms seem really different.
I implemented the change as described in bug report 118605.
To my horror, my system now freezes consistently.
However, I removed the ATI driver, and all my problems seem to be gone now.

sudo lspci -vvv

00:00.0 Host bridge: ATI Technologies Inc Radeon Xpress 200 Host Bridge (rev 01)
 Subsystem: Hewlett-Packard Company Unknown device 2a31
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
 Status: Cap- 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ >SERR- <PERR-
 Latency: 64
 Region 3: Memory at <ignored> (64-bit, non-prefetchable)
....

01:05.0 VGA compatible controller: ATI Technologies Inc RC410 [Radeon Xpress 200] (prog-if 00 [VGA controller])
 Subsystem: Hewlett-Packard Company Unknown device 2a31
 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B-
 Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
 Latency: 64 (2000ns min), Cache Line Size: 64 bytes
 Interrupt: pin A routed to IRQ 10
 Region 0: Memory at d0000000 (32-bit, prefetchable) [size=256M]
 Region 1: I/O ports at a000 [size=256]
 Region 2: Memory at feaf0000 (32-bit, non-prefetchable) [size=64K]
 Expansion ROM at feac0000 [disabled] [size=128K]
 Capabilities: [50] Power Management version 2
  Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 PME-Enable- DSel=0 DScale=0 PME-
 Capabilities: [80] Message Signalled Interrupts: Mask- 64bit- Queue=0/0 Enable-
  Address: 00000000 Data: 0000

Like Jan Hoogenraad, this error occurs every time for me using ATI card with the free driver. But my issue may be different, as I am able to do a Ctrl-Alt-Backspace.

On Ubuntu 8.04 AMD 64 ati radeon eXpress 200

When switching users my computer is still responsive and I can go back to the old session using ctr+alt+f-keys, but my monitor reports that the refresh rate is too high to display.

This however doesn't always happen... Sometimes it works flawlessly.

on 8.04, with ati catalyst8.5 radeon3650 card.
system still freezes (keyboard not responding
- disabling compiz has no effect

I just got done installing Hardy Heron on my laptop and began to experience the same problem. My laptop came equipped with an ATI 9600. After doing some successful logging in and out to get my system configured with its various users, I noticed that a notification box appeared at the top of my screen informing me of some new and nifty proprietary drivers just waiting to be installed that were pertinent to my video card. I clicked on it and went through the installation of the ATI accelerated graphics driver.

After installing this driver, I rebooted my system. From there I went back into my root account to finish configuring the system and cleaning up. I then hit the CTRL-ALT-BKSPC to go back to the X login screen. I experienced a black screen and my system froze up. I attempted to move over to one of my terminals using CTRL-ALT-F2 or CTRL-ALT-F3. Both of these endeavors were unsuccessful. I had to manually power the system down and reboot.

I was able to isolate the issue to the ATI accelerated graphics driver that I had installed. The only fix that I can suggest here is to disable and uninstall the driver through System>Administration>Hardware Drivers. After doing this, reboot your Ubuntu box and everything should be fine. You may lose a few bells and whistles in the process (i.e. 3D acceleration, eye candy, and 2D stuff).

I'm fairly sure that it's the ATI driver creating the problem and crashing X. I hope that this helps someone.

Same issue for me. This only happens with fglrx driver. ATI driver works fine.

01:00.0 VGA compatible controller: ATI Technologies Inc RV630 [Radeon HD 2600 Series] (prog-if 00 [VGA controller])
 Subsystem: VISIONTEK Unknown device 3330
 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
 Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
 Latency: 0, Cache Line Size: 16 bytes
 Interrupt: pin A routed to IRQ 16
 Region 0: Memory at c0000000 (64-bit, prefetchable) [size=256M]
 Region 2: Memory at bfee0000 (64-bit, non-prefetchable) [size=64K]
 Region 4: I/O ports at c000 [size=256]
 Expansion ROM at bfec0000 [disabled] [size=128K]
 Capabilities: <access denied>

Might as well add to the chatter here: Hardy/8.04; fglrx 8.47.3 on an AMD 690G-based system:

01:05.0 VGA compatible controller: ATI Technologies Inc RS690 [Radeon X1200 Series] (prog-if 00 [VGA controller])
        Subsystem: Foxconn International, Inc. Unknown device 0c8d
        Flags: bus master, fast devsel, latency 64, IRQ 18
        Memory at f0000000 (64-bit, prefetchable) [size=128M]
        Memory at feaf0000 (64-bit, non-prefetchable) [size=64K]
        I/O ports at d000 [size=256]
        Memory at fe900000 (32-bit, non-prefetchable) [size=1M]
        Capabilities: <access denied>

...switching users and then attempting to "log out" of the new session results in a black screen, frozen keyboard, and the Xorg process eating ~100% CPU. Turned off desktop effects for both accounts with the same result.

Killing Xorg remotely thankfully restarts it and renders the system usable again. At that point, switching consoles with the keyboard reveals no display corruption either.

The following snippets may be helpful. I'm not sure of the timing of the gdm error, that may be when I killall -9'd Xorg remotely.

auth.log:
Aug 9 21:47:38 badger gdm[8859]: pam_unix(gdm:session): session closed for user XXXXXX

syslog:
Aug 9 21:47:39 badger kernel: [496062.682675] [fglrx] interrupt source 10000000 successfully disabled!
Aug 9 21:47:39 badger kernel: [496062.682682] [fglrx] enable ID = 0x00000001
Aug 9 21:47:39 badger kernel: [496062.682685] [fglrx] Receive disable interrupt message with irqEnableMask: 10000000; dwIRQEnableId: 00000001
Aug 9 21:47:39 badger kernel: [496062.704524] [fglrx:firegl_lock_free] *ERROR* lock was not held by 37! (*lock=0x80000001)
Aug 9 21:47:39 badger kernel: [496062.704537] [fglrx:firegl_unlock] *ERROR* firegl_lock_free failed!
Aug 9 21:47:39 badger kernel: [496062.988780] [fglrx:firegl_lock_free] *ERROR* lock was not held by 1! (*lock=0x00000000)
Aug 9 21:47:39 badger kernel: [496062.988794] [fglrx:firegl_unlock] *ERROR* firegl_lock_free failed!
Aug 9 21:50:27 badger gdm[27731]: WARNING: gdm_slave_xioerror_handler: Fatal X error - Restarting :0

For users looking to recover without a complete reboot, you will probably need to run your sshd at a higher priority to be able to ssh in when a process like Xorg is hogging 100% CPU. To achieve this:
1. in /etc/init.d/ssh, add a --nicelevel ${SSHD_NICELEVEL:-0} option to the call to start-stop-daemon in the start case.
     (Or skip the :- and initialize SSHD_NICELEVEL=0 at the top of the file.)
2. in /etc/default/ssh, define SSHD_NICELEVEL=-12.

This will keep you from waiting hours for the cryptographic negotiation to find CPU time. Remember that all ssh login shells will inherit the meanness (so nice your processes if you're sharing the machine).

This package has become obsolete so we're closing out the bug report as WONTFIX.
Thanks for reporting it though!

Surprise!
The problem is back. Happens on a fresh install of 8.10, with Nvidia drivers in use.