Created attachment 38601 [details]
Xorg.0.log

When using the new evergreen_accel branch of the 
xf86-video-ati driver X crashes sometimes with the following backtrace:

[Xorg.0.log]
Backtrace:
[  2475.037] 0: /usr/bin/X (xorg_backtrace+0x28) [0x45d4f8]
[  2475.037] 1: /usr/bin/X (0x400000+0x59cc9) [0x459cc9]
[  2475.037] 2: /lib/libpthread.so.0 (0x367b600000+0xf470) [0x367b60f470]
[  2475.037] 3: /lib/libc.so.6 (memcpy+0xe1) [0x367ae808e1]
[  2475.037] 4: /usr/lib64/xorg/modules/libfb.so (fbBlt+0xf8) [0x7fd8f2a82388]
[  2475.037] 5: /usr/lib64/xorg/modules/libfb.so (fbBltStip+0x40) [0x7fd8f2a83130]
[  2475.037] 6: /usr/lib64/xorg/modules/libfb.so (fbPutZImage+0x19b) [0x7fd8f2a87d4b]
[  2475.037] 7: /usr/lib64/xorg/modules/libexa.so (0x7fd8f2859000+0x12004) [0x7fd8f286b004]
[  2475.037] 8: /usr/lib64/xorg/modules/libexa.so (0x7fd8f2859000+0x97a1) [0x7fd8f28627a1]
[  2475.037] 9: /usr/bin/X (0x400000+0xc8644) [0x4c8644]
[  2475.037] 10: /usr/bin/X (0x400000+0x45073) [0x445073]
[  2475.037] 11: /usr/bin/X (0x400000+0x485b1) [0x4485b1]
[  2475.037] 12: /usr/bin/X (0x400000+0x2140e) [0x42140e]
[  2475.037] 13: /lib/libc.so.6 (__libc_start_main+0xfd) [0x367ae1ecdd]
[  2475.037] 14: /usr/bin/X (0x400000+0x20fb9) [0x420fb9]
[  2475.037] Bus error at address 0x7fd8ec37c000
[  2475.037] 
Fatal server error:
[  2475.037] Caught signal 7 (Bus error). Server aborting
[  2475.037] 
[  2475.037] 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help. 
[/Xorg.0.log]

I'm not sure how to reproduce it right now, but i'm pretty sure
that one of these settings in xorg.conf do actually prevent the crash.

Option "RenderAccel" "off"
Option "EXANoDownloadFromScreen" "on"

(i had these in my config because of the cursor corruption
-> https://bugs.freedesktop.org/show_bug.cgi?id=29986)