915gm/945gm/XAA lockup with gray blocks when switching video mode

[Peter Clifton]

On Wed, 2007-10-10 at 21:17 +0000, Juan Pablo Salazar Bertin wrote:
> I'd like to add some things about this bug:
> 
> It has been reported also at https://bugs.freedesktop.org/show_bug.cgi?
> id=10586.
> 
> After several debugs, I've determined that the laptop hangs in the following 
> loop in file i830_driver.c:
> 
>    for(i = 0; i < 256; i++) {
>       OUTREG(PALETTE_A + (i << 2), pI830->savePaletteA[i]);
>    }


I got a slight feeling this (might) be HWCursor related.

I've seen the server crash many times in xf86_reload_cursors, but
haven't been able to get a back-trace.

I tried Option "SWcursor" "true", to disable HW cursor, and the crash
isn't reproducible with the mplayer playing trick I'd used before.

Realising that SWCursor disables DRI, (and thus this isn't a very clean
test), I patched the driver temporarily to avoid disabling DRI (means
funny pointer drawing if it goes over the XV window).

VT switching didn't restore the HW properly when hitting the console,
but it did not crash and I was able to switch back to the still working
X11 display.

I'm new to xorg debugging, so apologies if I'm being stupid here.

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)