[PATCH weston v2 2/2] compositor: add repaint delay timer

[Pekka Paalanen]

On Wed, 18 Mar 2015 14:44:52 -0700
Bill Spitzak <spitzak at gmail.com> wrote:

> Would it be possible to compute this repaint window as how long it took 
> to paint the previous frame, plus some small user-adjustable constant? 
> Or a more complex weighted average of recent frames?
> 
> I'm not sure if perhaps the necessary clock information is not 
> available, or that this idea would mess up the presentation feedback.

Currently we don't know when the frame compositing completes and how
much is just waiting for the next vblank to flip it on screen. Maybe we
will have a nice way in the future. Right now all we have AFAIK is
glFlush which simply does not do what we need, and glFinish which is a
blocking call so we'd need a thread to run it which requires moving all
EGL/GL calls into that thread basically and oh god the horror.

This topic was touched in the blog post comments at
http://ppaalanen.blogspot.fi/2015/02/weston-repaint-scheduling.html

Thanks,
pq

> On 03/18/2015 06:27 AM, Pekka Paalanen wrote:
> > From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> >
> > This timer delays the output_repaint towards the end of the refresh
> > period, reducing the time from repaint to present.
> >
> > The length of the repaint window can be set in weston.ini.