Comment 52 for bug 921236

Here we go...
# gdb X
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Reading symbols from /usr/bin/X...done.
(gdb) break I830ScreenInit
Function "I830ScreenInit" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (I830ScreenInit) pending.
(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 14:19:18 2012
(==) Using config directory: "/etc/X11/xorg.conf.d"
[tcsetpgrp failed in terminal_inferior: Die Operation ist nicht erlaubt]

Breakpoint 1, I830ScreenInit (scrnIndex=0, screen=0x178caa0, argc=1, argv=0x7fff1338fb78) at intel_driver.c:924
924 ScrnInfoPtr scrn = xf86Screens[screen->myNum];
(gdb) p &screen->BlockHandler
$1 = (ScreenBlockHandlerProcPtr *) 0x178ccb8
(gdb) watch *$
Hardware watchpoint 2: *$
(gdb) continue
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0
New value = (ScreenBlockHandlerProcPtr) 0x4352df <NoopDDA>
miScreenInit (pScreen=0x178caa0, pbits=0x0, xsize=<optimized out>, ysize=<optimized out>, dpix=<optimized out>, dpiy=<optimized out>, width=1920,
    rootDepth=24, numDepths=7, depths=0x178c2e0, rootVisual=33, numVisuals=2, visuals=0x1788e00) at miscrinit.c:267
267 pScreen->WakeupHandler = (ScreenWakeupHandlerProcPtr)NoopDDA;
(gdb) c
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0x4352df <NoopDDA>
New value = (ScreenBlockHandlerProcPtr) 0x4ab155 <xf86RotateBlockHandler>
0x00000000004ab9d7 in xf86CrtcRotate (crtc=0x1782c90) at xf86Rotate.c:475
475 pScreen->BlockHandler = xf86RotateBlockHandler;
(gdb) c
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0x4ab155 <xf86RotateBlockHandler>
New value = (ScreenBlockHandlerProcPtr) 0x7fb07ccd5c1e <I830BlockHandler>
I830ScreenInit (scrnIndex=0, screen=0x178caa0, argc=1, argv=0x7fff1338fb78) at intel_driver.c:1026
1026 if (!AddCallback(&FlushCallback, intel_flush_callback, scrn))
(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
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0x7fb07ccd5c1e <I830BlockHandler>
New value = (ScreenBlockHandlerProcPtr) 0x4ab155 <xf86RotateBlockHandler>
I830BlockHandler (i=0, blockData=0x0, pTimeout=0x7fff1338f9a8, pReadmask=0x7dc0c0) at intel_driver.c:750
750 (*screen->BlockHandler) (i, blockData, pTimeout, pReadmask);
(gdb) c
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0x4ab155 <xf86RotateBlockHandler>
New value = (ScreenBlockHandlerProcPtr) 0
xf86RotateBlockHandler (screenNum=0, blockData=0x0, pTimeout=0x7fff1338f9a8, pReadmask=0x7dc0c0) at xf86Rotate.c:274
274 (*pScreen->BlockHandler) (screenNum, blockData, pTimeout, pReadmask);
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()