Gentoo (amd64) using:
xorg-server-1.13.0 (tried 1.13.1 as well)
mesa-9.0 (tried 9.0.1 as well)
xf86-video-intel-2.20.13 (tried 2.20.16 as well)
00:02.0 VGA compatible controller: Intel Corporation 82G33/G31 Express Integrated Graphics Controller (rev 10)
If I enable the "cover switch" or "flip swith" effects for alt-tab, I will very often get a crash with alt-tab which ends in the i915_set_vertex_buffers function (line 1000 of gallium/drivers/i915/i915_state.c), trying to dereference a 0x0 buffer.
The buffers data structure contains just null pointers, and a stride value of 8, and line 1000 tries to dereference one of them. This may be the cause or the effect, that's not for me to judge :)
See attached backtrace. Turning off unredirect fullscreen windows did not affect it (there were some related bugs a year or two ago)
Created attachment 72225 [details] [review]
Backtrace of crash
This is an i915g bug, which isn't supported by us...changing the component.
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