i915: hangcheck timer elapsed

[Chris Wilson]

On Tue, 22 Nov 2011 19:44:52 -0800, Keith Packard <keithp at keithp.com> wrote:
> On Tue, 22 Nov 2011 14:43:00 -0800 (PST), Linus Torvalds <torvalds at linux-foundation.org> wrote:
> 
> > X is hung, but I can at least switch VT's and send this from a text 
> > terminal..
> 
> Yeah, the GPU is locked up; doesn't look like we did anything wrong in
> the kernel here; it's happily waiting for the GPU which isn't moving.
> 
> Presumably a bug in either the 2D driver or Mesa. I'm betting the 2D
> driver, and yes, I'm trying to fix this (by deleting code, which is
> always the best way).

Indeed the fix landed in 2.13.902 by removing some erroneous hardcoded
maxima, and since we currently have lots of duplication in the code the
video paths remained broken until 2.15.0.

commit 3c5b1399e29ef577b8b91655b5e1c215d1b6dfbb
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Tue Nov 9 20:20:06 2010 +0000

    i915: Disable maximum state addresses
    
    As the kernel controls the relocation of state buffers, we should not
    hard code the maximum permissible value for them.
    
    Fixes an eventual hang with full-gtt.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre