[Intel-gfx] panning crash

[Chris Wilson]

On Sat, Jun 13, 2015 at 02:17:34AM -0400, Felix Miata wrote:
> Dell Optiplex GX280
> P4 32 bit Hyperthreading enabled 0F34 2.8GHz CPU
> 00:02.0 VGA compatible controller: Intel Corporation 82915G/GV/910GL Integrated Graphics Controller (rev 04)
> 
> /etc/X11/xinit/xinitrc.d/setup contains:
> xrandr --fbmm 387x218 --fb 2560x1440 --output VGA1 --mode 1920x1440 --panning 2560x1440
> 
> Panning mouse out of initial CRTC desktop space into virtual desktop space and back in
> some installations causes crash, in others not. Can someone here tell if this is a kernel,
> server or other issue and not a driver issue from a look at Xorg.0.log? My suspicion is
> kernel as primary if not sole.

I think the crash is in the rejection handling code. If the kernel
rejects the modeset, we try again with via a shadow. The crash is very
unexpected. You can run the stacktraces though addr2line (e.g.
addr2line -i -e /usr/lib/xorg/modules/drivers/intel_drv.so 0x638f7
0x68fbc 0x6a02b) but also compiling your own ddx with
--enable-debug=full would be very useful. A drm.debug=6 dmesg would tell
you what is going on kernel side.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre