[Intel-gfx] [PATCH 4/8] drm/i915: DRRS calls based on frontbuffer

[Daniel Vetter]

On Mon, Dec 15, 2014 at 07:45:13PM +0530, Kannan, Vandana wrote:
> 
> 
> On 15-Dec-14 3:27 PM, Daniel Vetter wrote:
> >On Thu, Dec 11, 2014 at 02:22:53AM +0530, Vandana Kannan wrote:
> >>Calls have been added to invalidate/flush DRRS whenever invalidate/flush is
> >>called as part of frontbuffer tracking.
> >>Apart from calls as a result of GEM tracking to fb invalidate/flush, a
> >>call has been added to invalidate fb obj from crtc_page_flip as well. This
> >>is to track busyness through flip calls.
> >
> >That shouldn't be required really. Or maybe I misunderstand what you mean
> >here ...
> >
> Last month when I was implementing this, DRRS worked as expected only when
> this call was made from crtc_page_flip. I checked the recent code today and
> as you mentioned above, this call isn't required.
> I can remove this call from this patch..
> Having said that, sometime back I observed that Android used crtc_page_flip
> and its possible that DRRS would break in that scenario without this call to
> invalidate..

We might have had a bug, but in your current patch you only move it
around. You no longer add a new call. So I think we can just remove this.

But please make sure it still works for Android, otherwise we have a big
problem. The intel_frontbuffer_flip_prepare should result in a _flush call
in the frontbuffer tracking code eventually, so it should work. But better
check.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch