Re: [PATCH] drm/i915/gen9: Increase PCODE request timeout to 100ms

Chris Wilson
2017-02-21T09:37:30Z

On Tue, Feb 21, 2017 at 11:22:12AM +0200, Imre Deak wrote:
> On Mon, Feb 20, 2017 at 04:05:33PM +0000, Chris Wilson wrote:
> > So that our preempt-off period doesn't grow completely unchecked, or do
> > we need that 34ms loop?
>
> Yes, that's at least how I understand it. Scheduling away is what let's
> PCODE start servicing some other request than ours or go idle. That's
> in a way what we see when the preempt-enabled poll times out.

I was thinking along the lines of if it was just busy/unavailable for the
first 33ms that particular time, it just needed to sleep until ready.
Once available, the next request ran in the expected 1ms.

Do you not see any value in trying a sleeping loop? Perhaps compromise
and have the preempt-disable timeout increase each iteration.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre