[Maverick only] Pressing printscreen hangs keyboard

[Delan Azabani]

I believe this to be a relatively serious bug. In maverick, if I press the printscreen key, the keyboard will stop working until I restart the computer. After I hit printscreen, any other keys I press will add this to /var/log/messages:

[ 152.650996] SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) thaw-filesystems(J) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W) dump-ftrace-buffer(Z)
---
Architecture: amd64
DistroRelease: Ubuntu 10.10
NonfreeKernelModules: nvidia
Package: linux 2.6.35.2.2
PackageArchitecture: amd64
ProcEnviron:
 LANGUAGE=en_US:en_AU:en_GB:en
 LANG=en_US.utf8
 SHELL=/bin/bash
Tags: maverick
Uname: Linux 2.6.35-020635rc3-generic x86_64
UnreportableReason: The running kernel is not an Ubuntu kernel
UserGroups: adm admin audio cdrom dialout dip fax floppy fuse lpadmin netdev plugdev sudo tape video

[Delan Azabani (azabani)]

Additional information: the printscreen key only seems to hang the keyboard if I have ever pressed the ALT key during the computer being on. If I've just started the computer, I can safely use the printscreen key until I use the ALT key - even pressing it by itself.

[Tobias Wolf (towolf)]

I have the same issue starting with Linux 2.6.35-rc2

Delan, what type of computer do you see this on? I have a Lenovo Thinkpad x301.

It appears that somehow pressing PrintScr alone trigger the magic SysReq mode. On my laptop normally SysReq is on Fn+PrintScr. But to trigger magic SysReq it is enough to press Alt+PrintScr+<letter>. No Fn is necessary.

Now it triggers SysReq with PrintScr alone and waits for the letter. And the keyboard is blocked during that time. Any wrong key then and the system goes down. Pressing Alt again seems to release this mode.

[Tobias Wolf (towolf)]

Sounds like: http://thread.gmane.org/gmane.linux.kernel.input/13319

[Delan Azabani (azabani)]

Uh... my computer is a custom build, with a Gigabyte EP45T-UD3P mainboard, and a Microsoft Multimedia keyboard.

[Tobias Wolf (towolf)]

Yes, going by the link above it should probably affect everybody. Are there any other duplicate bugs about this?

[Jeremy Foshee (jeremyfoshee)]

Hi Delan,

Please be sure to confirm this issue exists with the latest development release of Ubuntu. ISO CD images are available from http://cdimage.ubuntu.com/daily-live/current/ . If the issue remains, please run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 592042

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

    [This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[Delan Azabani (azabani)]

Jeremy, unfortunately I can't test an upstream kernel as make-kpkg won't create an initrd, which causes a kernel package whenever I compile and run an upstream kernel. See this bug for more details: https://bugs.launchpad.net/bugs/592927

[Tobias Wolf (towolf)]

Delan, you don’t need to build the upstream kernel, just install a mainline kernel from here:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.35-rc3-maverick/

[Delan Azabani (azabani)]

The problem still occurs in the latest kernel from that link, 2.6.35-020635rc3.

[Delan Azabani (azabani)]

apport information

[dORSY (dorsyka)]

For me the gnome exits and my PC shuts down (goes into suspend?) when I press PrintScreen...

[Mikkel Munch Mortensen (3xm)]

I'm experiencing this too. I did some testing and it seems it only happens when a window is active. If I have no windows, only the desktop shown, this does not happen. But when I open a window and press Print Screen, keyboard stops working. Then the top/bottom panels flicker (sometimes disappears) and window decorations disappear. After a little while, the computer shuts down.

Initially I thought it was related to X or something like that, but maybe it's the SysRq thing?

I was about to file a new bug about this via Apport (but then I decided to ask The Google before submitting anything). Somewhere in the steps, it gave me the following to submit:

BUG: unable to handle kernel NULL pointer dereference at 00000008
IP: [<c03e4175>] fb_release+0x25/0x60
Call Trace:
 [<c021abaf>] ? __fput+0xdf/0x1f0
 [<c021acdd>] ? fput+0x1d/0x30
 [<c02175cc>] ? filp_close+0x4c/0x80
 [<c0217675>] ? sys_close+0x75/0xc0
 [<c05cdc1c>] ? syscall_call+0x7/0xb
Code: bc 27 00 00 00 00 55 89 e5 83 ec 08 89 1c 24 89 74 24 04 0f 1f 44 00 00 8b 5a 70 8d 73 08 89 f0 e8 41 83 1e 00 8b 83 0c 03 00 00 <8b> 48 08 85 c9 74 0f ba 01 00 00 00 89 d8 ff d1 8b 83 0c 03 00
EIP: [<c03e4175>] fb_release+0x25/0x60 SS:ESP 0068:f4deff3c
CR2: 0000000000000008

[Mikkel Munch Mortensen (3xm)]

Okay, sorry to be spamming. But I just realized that alpha3 was out (I was running alpha2). After installing a fresh alpha3, the problem seems to be gone.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 592042

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]