[Bug 974041] Re: KWin option of auto-suspending for fullscreen windows often causes X to crash in libdrm_intel

[Roman]

I have eventually found a way to obtain detailed debug info when X server crashing.
I am executing the following command from a text console:
sudo gdb -p $(pidof X) -batch -ex 'handle all nostop' -ex 'handle all pass'  -ex 'handle 11 stop' -ex 'cont' -ex 'bt full' -ex 'cont' > ~/Xcrash.txt
Then I return back to the graphical session and try to trigger the crash.
I have collected already a few of such backtraces, and I am a bit surprised that apparently they ALL are VERY different.
In general, it seems as if KWin erases some important stuff that is further dereferenced in libdrm functions, and it is rather random which function will trigger the crash.

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https://bugs.launchpad.net/bugs/974041

Title:
  KWin option of auto-suspending for fullscreen windows often causes X
  to crash in libdrm_intel

Status in “libdrm” package in Ubuntu:
  New

Bug description:
  Ubuntu release: KUbuntu 12.04 (beta)
  libdrm-intel1 2.4.32, xserver-xorg-core 1.11.4

  In the Ubuntu 12.04 with the KWin option "suspend desktop effects for fullscreen windows"
  enabled, I often get X crashes. This usually occures when I just exit from a fullscreen application,
  before the usual KDE desktop should show up. Such thing usually happens with applications running
  under wine, but recently I got a similar crash with the usual KDE screensaver. X server just restarts
  and all unsaved work in my KDE session gets lost.

  In the Xorg.0.log.old I find some stack backtrace, which may differ from case to case, but it always
  ends in libdrm_intel. I attach a few examples below. I realize that these logs are possibly not very useful
  (there are only raw addresses), but I have no idea how to make X to dump more detailed backtrace,
  with full debug info. These crashes are rather well reproducible, and if someone explains how to get
  more detailed information, I will gladly do this.

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