Intel i915 freeze on latest git

[Chris Wilson]

On Tue, 1 Feb 2011 08:31:12 -0800, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> The bisect is interesting, I'd have expected a failure when we
> re-enabled rc6 on ILK or when we fixed up the ring buffer init.

Yes, that was my instinct as well.

Though that patch does do have one subtlety:

ironlake_enable_rc6():
+      I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);

So it appears the patch may in fact be enabling render standby, when it
was actually dropped in

commit 88271da3f3da75d6eaef5e768c82a1627edf7088
Author: Jesse Barnes <jbarnes at virtuousgeek.org>
Date:   Wed Jan 5 12:01:24 2011 -0800

    drm/i915: re-enable rc6 support for Ironlake+

intel_enable_clock_gating():
-	I915_WRITE(MCHBAR_RENDER_STANDBY,
-	           I915_READ(MCHBAR_RENDER_STANDBY) & ~RCX_SW_EXIT);


So, if this is the issue, then simply commenting out the tweaking of
RSTDBYCTL in ironlake_enable_rc6() should prevent the hang.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre