[Intel-gfx] [PATCH] drm/i915: Only start with the fake-irq timer if interrupts are dead

[Chris Wilson]

On Fri, Feb 17, 2017 at 02:59:44PM +0000, Tvrtko Ursulin wrote:
> 
> On 17/02/2017 11:55, Chris Wilson wrote:
> >As a backup to waiting on a user-interrupt from the GPU, we use a heavy
> >and frequent timer to wake up the waiting process should we detect an
> >inconsistency whilst waiting. After seeing a "missed interrupt", the
> >next time we wait, we restart the heavy timer. This patch is more
> >reluctant to restart the timer and will only do so if we have not see any
> >interrupts since when we started the fake irq timer. If we are seeing
> >interrupts, then the waiters are being woken normally and we had an
> >incoherency that caused to miss last time - that is unlikely to reoccur
> >and so taking the risk of stalling again seems pragmatic.
> >
> >Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> >Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> Very soothing now that I have discovered the pre-existing behaviour. :)
> 
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Thanks both of you for the review and suggestions, pushed to try and
soothe CI even more.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre