Re: [PATCH 14/15] drm/i915: Track frontbuffer invalidation/flushing

Daniel Vetter
2014-06-17T09:33:49Z

On Tue, Jun 17, 2014 at 09:10:14AM +0100, Chris Wilson wrote:
> On Tue, Jun 17, 2014 at 09:52:17AM +0200, Daniel Vetter wrote:
> > On Tue, Jun 17, 2014 at 08:00:05AM +0100, Chris Wilson wrote:
> > > On Mon, Jun 16, 2014 at 07:51:34PM +0200, Daniel Vetter wrote:
> > > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > > > index b8359f4a6dc4..dfdbf2a02844 100644
> > > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > > @@ -2755,6 +2755,8 @@ intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
> > > >
> > > > dev_priv->display.update_primary_plane(crtc, fb, x, y);
> > > >
> > > > + intel_frontbuffer_flush(dev, INTEL_FRONTBUFFER_PRIMARY(pipe));
> > >
> > > Conceptually all of these are just intel_fb_flip_complete. It may be
> > > easier in your tracking scheme to have:
> > >
> > > intel_fb_flip() { intel_fb_flip_prepare(); intel_fb_fip_complete(); }
> >
> > Yeah, this is just the direct flush for synchronous updates. Implementing
> > that as a prepare+complete is imo too confusing - the entire point of
> > prepare+complete is to catch an intermediate invalidates and not complete
> > the flush and so only really required for async flips. Hence why I prefer
> > to only do the full prepare+complete dance where needed. Otherwise there
> > is nothing special about flips.
>
> I just prefer to have the like operations having like names. The key
> point here is that we just want to treat the set-plane operations as a
> synchronous flip, which is distinct to the invalidate/flush operations on
> an active frontbuffer.

Well the main thing is the setplane is a flush operation. Flip is also a
flush, but an asynchronous one. Maybe s/flip/flush/ instead to make it
clear that the special part isn't that it's a flip, but that it's
two-stage?
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch