Description of problem:
just logged in to gnome desktop, then opened system settings. 
last symptom: it produced a distorted picture on the opened window, desktop not reacting any more. 


Version-Release number of selected component:
xorg-x11-server-Xorg-1.12.3-2.fc17

Additional info:
libreport version: 2.0.16
abrt_version:   2.0.15
kernel:         3.6.1-1.fc17.i686

backtrace:
:0: /usr/bin/Xorg (xorg_backtrace+0x4a) [0x80ac45a]
:1: /usr/bin/Xorg (mieqEnqueue+0x22b) [0x81aacfb]
:2: /usr/bin/Xorg (0x8047000+0x4589c) [0x808c89c]
:3: /usr/bin/Xorg (xf86PostMotionEventM+0x253) [0x80d9ec3]
:4: /usr/bin/Xorg (xf86PostMotionEvent+0xaa) [0x80da10a]
:5: /usr/lib/xorg/modules/input/synaptics_drv.so (0xb70ef000+0x477e) [0xb70f377e]
:6: /usr/lib/xorg/modules/input/synaptics_drv.so (0xb70ef000+0x6c61) [0xb70f5c61]
:7: /usr/bin/Xorg (0x8047000+0x82302) [0x80c9302]
:8: /usr/bin/Xorg (0x8047000+0xa8693) [0x80ef693]
:9: (vdso) (__kernel_sigreturn+0x0) [0xb7799400]
:10: (vdso) (__kernel_vsyscall+0x10) [0xb7799424]
:11: /lib/libc.so.6 (ioctl+0x19) [0x443c4459]
:12: /lib/libdrm.so.2 (drmIoctl+0x34) [0x47679b74]
:13: /lib/libdrm.so.2 (drmCommandWriteRead+0x3d) [0x4767c69d]
:14: /lib/libdrm_radeon.so.1 (0xb7702000+0x17c2) [0xb77037c2]
:15: /lib/libdrm_radeon.so.1 (0xb7702000+0x1a35) [0xb7703a35]
:16: /lib/libdrm_radeon.so.1 (radeon_bo_map+0x1b) [0xb770504b]
:17: /usr/lib/xorg/modules/drivers/radeon_drv.so (0xb7565000+0x87e06) [0xb75ece06]
:18: /usr/lib/xorg/modules/libexa.so (0xb7539000+0x4049) [0xb753d049]
:19: /usr/lib/xorg/modules/libexa.so (0xb7539000+0x75e5) [0xb75405e5]
:20: /usr/lib/xorg/modules/libexa.so (0xb7539000+0x4169) [0xb753d169]
:21: /usr/lib/xorg/modules/libexa.so (0xb7539000+0x111dd) [0xb754a1dd]
:22: /usr/lib/xorg/modules/libexa.so (0xb7539000+0xa449) [0xb7543449]
:23: /usr/bin/Xorg (0x8047000+0x10e9be) [0x81559be]
:24: /usr/bin/Xorg (miPaintWindow+0x266) [0x81ab9d6]
:25: /usr/bin/Xorg (miWindowExposures+0xbf) [0x81abb1f]
:26: /usr/bin/Xorg (0x8047000+0x992be) [0x80e02be]
:27: /usr/bin/Xorg (miHandleValidateExposures+0x96) [0x81c4326]
:28: /usr/bin/Xorg (UnmapWindow+0x21c) [0x80a592c]
:29: /usr/bin/Xorg (DeleteWindow+0x38) [0x80a59a8]
:30: /usr/bin/Xorg (0x8047000+0x53cfd) [0x809acfd]
:31: /usr/bin/Xorg (FreeResource+0xec) [0x809b4cc]