[Mesa-dev] [PATCH 05/10] i965: Use Global GTT for Sandybridge post-sync non-zero workaround.

[Eric Anholt]

Kenneth Graunke <kenneth at whitecape.org> writes:

> The kernel doesn't even set up the aliasing PPGTT on Sandybridge, so any
> writes marked as PPGTT will likely just get dropped on the floor.

The hardware bug is that writes not marked as GTT are still looked up in
the GTT anyway.

The kernel does set up the PPGTT, which is how we found we needed to put
in the kernel workaround based on DOMAIN_INSTRUCTION (of binding the
target buffer to the gtt as well as the ppgtt, since the writes landed
in the wrong place)

I don't think this patch will change anything, but it seems reasonable
if the commit message is updated.
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