Comment 10 for bug 774978

I am having the same trouble with an i915. My system is stock everything (upgraded from maverick to natty) except running the PAE kernel and the "ubuntu classic" gdm session. A freeze sometimes occurs within about five minutes of booting up and logging in, but doesn't happen at all if the session survives longer than that, as it usually does. I don't use Firefox, so it's not caused only by that. A freeze can happen randomly even when just popping up any menu. Then it restarts the session using tty8 and doesn't crash again. Here's a trace from the log file:

[ 907.242] Backtrace:
[ 907.242] 0: /usr/bin/X (xorg_backtrace+0x3b) [0x80eab1b]
[ 907.243] 1: /usr/bin/X (0x8048000+0x5fac8) [0x80a7ac8]
[ 907.243] 2: (vdso) (__kernel_rt_sigreturn+0x0) [0xb76f440c]
[ 907.243] 3: /usr/bin/X (_CallCallbacks+0x3e) [0x8074e1e]
[ 907.243] 4: /usr/bin/X (WriteToClient+0x267) [0x80a7607]
[ 907.243] 5: /usr/lib/xorg/modules/extensions/libdri2.so (ProcDRI2WaitMSCReply+0x62) [0xb72a6bf2]
[ 907.243] 6: /usr/lib/xorg/modules/extensions/libdri2.so (DRI2WaitMSCComplete+0x75) [0xb72a4fc5]
[ 907.243] 7: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb7243000+0x226bc) [0xb72656bc]
[ 907.243] 8: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb7243000+0x87d2) [0xb724b7d2]
[ 907.243] 9: /lib/i386-linux-gnu/libdrm.so.2 (drmHandleEvent+0xf5) [0xb7294665]
[ 907.243] 10: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb7243000+0x7937) [0xb724a937]
[ 907.243] 11: /usr/bin/X (WakeupHandler+0x52) [0x8074602]
[ 907.243] 12: /usr/bin/X (WaitForSomething+0x1ba) [0x80a1f3a]
[ 907.243] 13: /usr/bin/X (0x8048000+0x27f1e) [0x806ff1e]
[ 907.243] 14: /usr/bin/X (0x8048000+0x1a81c) [0x806281c]
[ 907.243] 15: /lib/i386-linux-gnu/libc.so.6 (__libc_start_main+0xe7) [0xb740fe37]
[ 907.243] 16: /usr/bin/X (0x8048000+0x1a411) [0x8062411]
[ 907.243] Segmentation fault at address 0xb45e9008
[ 907.243] Caught signal 11 (Segmentation fault). Server aborting