[Intel-gfx] [PATCH] drm/i915: Flush pipecontrol post-sync writes

[Jani Nikula]

On Wed, 26 Aug 2015, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Wed, Aug 26, 2015 at 11:16:34AM +0200, Daniel Vetter wrote:
>> On Fri, Aug 21, 2015 at 04:08:41PM +0100, Chris Wilson wrote:
>> > In order to flush the results from in-batch pipecontrol writes (used for
>> > example in glQuery) before declaring the batch complete (and so declaring
>> > the query results coherent), we need to set the FlushEnable bit in our
>> > flushing pipecontrol. The FlushEnable bit "waits until all previous
>> > writes of immediate data from post-sync circles are complete before
>> > executing the next command".
>> > 
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> > Cc: stable at vger.kernel.org
>> 
>> Do we have an igt/piglit failing somewhere (igt kinda preferred) or a
>> bugzilla or why is this cc: stable?
>
> I get GPU hangs on byt without flushing these writes (running ue4).
> piglit has examples where the flush is required for correct rendering.

Daniel, does this satisfy your question? We've had an r-b from Ville for
a long time.

BR,
Jani.


> -Chris
>
> -- 
> Chris Wilson, Intel Open Source Technology Centre
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-- 
Jani Nikula, Intel Open Source Technology Center