[Mesa-dev] [PATCH] i965: Fix GPU hangs when a blorp batch is the first thing to execute.

[Chris Wilson]

On Wed, May 01, 2013 at 04:28:08PM -0700, Eric Anholt wrote:
> The GPU apparently goes looking for constants even though there are no
> shader stages enabled, and gets stuck because we haven't told it there are
> no constants to collect.  If any other user of the 3D pipeline had run
> (even the Render accel of the X server!) since power on, then the in-GPU
> constant buffers would have been set up with some contents we didn't use,
> and we would succeed.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=56416
> NOTE: This is a candidate for the stable branches.

The collorary to this is that DynamicStateUpperBound is programmed to an
unsafe value and should be (0x7fff0000 | 1) for most of our hardware. The
actual value to program requires information not easily reported by the
kernel (just like the mappable aperture size).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre