Comment 58 for bug 921236

not sure which backtrace you need, so here are all of them. :)

(gdb) delete 2
(gdb) break xf86CrtcScreenInit
Breakpoint 3 at 0x49f37f: file xf86Crtc.c, line 774.
(gdb) run
Starting program: /usr/bin/X
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".

X.Org X Server 1.12.0
Release Date: 2012-03-04
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.2.11-1-ARCH x86_64
Current Operating System: Linux utahraptor 3.2.11-1-ARCH #1 SMP PREEMPT Thu Mar 15 09:19:02 CET 2012 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-linux root=/dev/mapper/ssdvg-arch ro quiet
Build Date: 19 March 2012 10:45:43AM

Current version of pixman: 0.24.4
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Mar 19 15:32:58 2012
(==) Using config directory: "/etc/X11/xorg.conf.d"
[tcsetpgrp failed in terminal_inferior: Die Operation ist nicht erlaubt]

Breakpoint 1, xf86CrtcRotate (crtc=0x17d0fe0) at xf86Rotate.c:385
385 ScrnInfoPtr pScrn = crtc->scrn;
(gdb) backtrace
#0 xf86CrtcRotate (crtc=0x17d0fe0) at xf86Rotate.c:385
#1 0x00007f53f24923dc in intel_crtc_apply (crtc=0x17d0fe0) at intel_display.c:370
#2 0x00007f53f24927f1 in intel_crtc_set_mode_major (crtc=0x17d0fe0, mode=0x17d10c8, rotation=1, x=0, y=0) at intel_display.c:461
#3 0x00000000004a0d29 in xf86CrtcSetModeTransform (crtc=0x17d0fe0, mode=0x17d10c8, rotation=1, transform=0x0, x=0, y=0) at xf86Crtc.c:303
#4 0x00000000004a1524 in xf86SetDesiredModes (scrn=0x17c3660) at xf86Crtc.c:2677
#5 0x00007f53f2497ab7 in I830EnterVT (scrnIndex=0, flags=0) at intel_driver.c:1149
#6 0x00007f53f24975f0 in I830ScreenInit (scrnIndex=0, screen=0x17dbaa0, argc=1, argv=0x7fff2404e4c8) at intel_driver.c:1020
#7 0x0000000000431e27 in AddScreen (pfnInit=0x7f53f24971f6 <I830ScreenInit>, argc=1, argv=0x7fff2404e4c8) at dispatch.c:3909
#8 0x000000000046db85 in InitOutput (pScreenInfo=0x7db0c0, argc=1, argv=0x7fff2404e4c8) at xf86Init.c:817
#9 0x00000000004219e3 in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:204
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x17d1c90) at xf86Rotate.c:385
385 ScrnInfoPtr pScrn = crtc->scrn;
(gdb) backtrace
#0 xf86CrtcRotate (crtc=0x17d1c90) at xf86Rotate.c:385
#1 0x00007f53f24923dc in intel_crtc_apply (crtc=0x17d1c90) at intel_display.c:370
#2 0x00007f53f24927f1 in intel_crtc_set_mode_major (crtc=0x17d1c90, mode=0x17d1d78, rotation=1, x=1920, y=0) at intel_display.c:461
#3 0x00000000004a0d29 in xf86CrtcSetModeTransform (crtc=0x17d1c90, mode=0x17d1d78, rotation=1, transform=0x0, x=1920, y=0) at xf86Crtc.c:303
#4 0x00000000004a1524 in xf86SetDesiredModes (scrn=0x17c3660) at xf86Crtc.c:2677
#5 0x00007f53f2497ab7 in I830EnterVT (scrnIndex=0, flags=0) at intel_driver.c:1149
#6 0x00007f53f24975f0 in I830ScreenInit (scrnIndex=0, screen=0x17dbaa0, argc=1, argv=0x7fff2404e4c8) at intel_driver.c:1020
#7 0x0000000000431e27 in AddScreen (pfnInit=0x7f53f24971f6 <I830ScreenInit>, argc=1, argv=0x7fff2404e4c8) at dispatch.c:3909
#8 0x000000000046db85 in InitOutput (pScreenInfo=0x7db0c0, argc=1, argv=0x7fff2404e4c8) at xf86Init.c:817
#9 0x00000000004219e3 in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:204
(gdb) c
Continuing.

Breakpoint 3, xf86CrtcScreenInit (screen=0x17dbaa0) at xf86Crtc.c:774
774 {
(gdb) backtrace
#0 xf86CrtcScreenInit (screen=0x17dbaa0) at xf86Crtc.c:774
#1 0x00007f53f24976cb in I830ScreenInit (scrnIndex=0, screen=0x17dbaa0, argc=1, argv=0x7fff2404e4c8) at intel_driver.c:1036
#2 0x0000000000431e27 in AddScreen (pfnInit=0x7f53f24971f6 <I830ScreenInit>, argc=1, argv=0x7fff2404e4c8) at dispatch.c:3909
#3 0x000000000046db85 in InitOutput (pScreenInfo=0x7db0c0, argc=1, argv=0x7fff2404e4c8) at xf86Init.c:817
#4 0x00000000004219e3 in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:204
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x17d0fe0) at xf86Rotate.c:385
385 ScrnInfoPtr pScrn = crtc->scrn;
(gdb) backtrace
#0 xf86CrtcRotate (crtc=0x17d0fe0) at xf86Rotate.c:385
#1 0x00007f53f24923dc in intel_crtc_apply (crtc=0x17d0fe0) at intel_display.c:370
#2 0x00007f53f2494a38 in intel_xf86crtc_resize (scrn=0x17c3660, width=3200, height=1080) at intel_display.c:1424
#3 0x00000000004a8f60 in xf86RandR12ScreenSetSize (pScreen=0x17dbaa0, width=3200, height=1080, mmWidth=846, mmHeight=285) at xf86RandR12.c:707
#4 0x00000000004a9cd1 in xf86RandR12CreateScreenResources (pScreen=0x17dbaa0) at xf86RandR12.c:841
#5 0x000000000049e9f4 in xf86CrtcCreateScreenResources (screen=0x17dbaa0) at xf86Crtc.c:728
#6 0x0000000000421a4b in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:216
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x17d1c90) at xf86Rotate.c:385
385 ScrnInfoPtr pScrn = crtc->scrn;
(gdb) backtrace
#0 xf86CrtcRotate (crtc=0x17d1c90) at xf86Rotate.c:385
#1 0x00007f53f24923dc in intel_crtc_apply (crtc=0x17d1c90) at intel_display.c:370
#2 0x00007f53f2494a38 in intel_xf86crtc_resize (scrn=0x17c3660, width=3200, height=1080) at intel_display.c:1424
#3 0x00000000004a8f60 in xf86RandR12ScreenSetSize (pScreen=0x17dbaa0, width=3200, height=1080, mmWidth=846, mmHeight=285) at xf86RandR12.c:707
#4 0x00000000004a9cd1 in xf86RandR12CreateScreenResources (pScreen=0x17dbaa0) at xf86RandR12.c:841
#5 0x000000000049e9f4 in xf86CrtcCreateScreenResources (screen=0x17dbaa0) at xf86Crtc.c:728
#6 0x0000000000421a4b in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:216
(gdb) c
Continuing.
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning: Multiple interpretations of "Caps_Lock+AnyOfOrNone(all)"
> Using last definition for duplicate fields
> Warning: Multiple interpretations of "Shift_L+AnyOfOrNone(all)"
> Using last definition for duplicate fields
> Warning: Type "ONE_LEVEL" has 1 levels, but <LSGT> has 4 symbols
> Ignoring extra symbols
> Warning: Type "ONE_LEVEL" has 1 levels, but <BKSL> has 2 symbols
> Ignoring extra symbols
> Warning: Type "ONE_LEVEL" has 1 levels, but <RALT> has 2 symbols
> Ignoring extra symbols
Errors from xkbcomp are not fatal to the X server

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) backtrace
#0 0x0000000000000000 in ?? ()
#1 0x00000000004ab20b in xf86RotateBlockHandler (screenNum=0, blockData=0x0, pTimeout=0x7fff2404e2f8, pReadmask=0x7dc0c0) at xf86Rotate.c:274
#2 0x00007f53f2496cb1 in I830BlockHandler (i=0, blockData=0x0, pTimeout=0x7fff2404e2f8, pReadmask=0x7dc0c0) at intel_driver.c:750
#3 0x0000000000435327 in BlockHandler (pTimeout=0x7fff2404e2f8, pReadmask=0x7dc0c0) at dixutils.c:392
#4 0x000000000055b9cd in WaitForSomething (pClientsReady=0x379c840) at WaitFor.c:219
#5 0x0000000000431885 in Dispatch () at dispatch.c:366
#6 0x0000000000421c30 in main (argc=1, argv=0x7fff2404e4c8, envp=<optimized out>) at main.c:287
(gdb)