(gdb) break xf86CrtcRotate
Breakpoint 1 at 0x4ab667: file xf86Rotate.c, line 385.
(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 15:23:31 2012
(==) Using config directory: "/etc/X11/xorg.conf.d"
[tcsetpgrp failed in terminal_inferior: Die Operation ist nicht erlaubt]

Breakpoint 1, xf86CrtcRotate (crtc=0x1c9ffe0) at xf86Rotate.c:385
385         ScrnInfoPtr         pScrn = crtc->scrn;
(gdb) s
386         xf86CrtcConfigPtr   xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
(gdb) s
388         ScreenPtr           pScreen = screenInfo.screens[pScrn->scrnIndex];
(gdb) p &xf86_config->BlockHandler
$1 = (ScreenBlockHandlerProcPtr *) 0x1c9fe38
(gdb) watch *$
Hardware watchpoint 2: *$
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x1ca0c90) at xf86Rotate.c:385
385         ScrnInfoPtr         pScrn = crtc->scrn;
(gdb) c
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0
New value = (ScreenBlockHandlerProcPtr) 0x4352df <NoopDDA>
xf86CrtcRotate (crtc=0x1ca0c90) at xf86Rotate.c:475
475                         pScreen->BlockHandler = xf86RotateBlockHandler;
(gdb) c
Continuing.
Hardware watchpoint 2: *$

Old value = (ScreenBlockHandlerProcPtr) 0x4352df <NoopDDA>
New value = (ScreenBlockHandlerProcPtr) 0
xf86CrtcScreenInit (screen=0x1caaaa0) at xf86Crtc.c:815
815         _xf86_di_dga_init_internal(screen);
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x1c9ffe0) at xf86Rotate.c:385
385         ScrnInfoPtr         pScrn = crtc->scrn;
(gdb) c
Continuing.

Breakpoint 1, xf86CrtcRotate (crtc=0x1ca0c90) at xf86Rotate.c:385
385         ScrnInfoPtr         pScrn = crtc->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

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