[Intel-gfx] [PATCH 5/5] drm/i915: Use atomic commits for legacy page_flips

[Chris Wilson]

On Tue, Jun 21, 2016 at 04:23:42PM +0200, Daniel Vetter wrote:
> Adding Maarten/Daniela since I'm going on vacation.
> -Daniel
> 
> On Mon, Jun 20, 2016 at 8:30 PM, Matthew Auld
> <matthew.william.auld at gmail.com> wrote:
> > I seem to be hitting some issues with this, at least in gnome-shell
> > which I bisected to this commit. Somewhat hard to describe but the
> > background window or desktop is partiality and intermittently drawn,
> > almost like a flicker onto the foreground window, title-bar etc.
> > typically during any kind of transition animation, like switching
> > windows, though sometimes just at random. Any ideas, I take it you
> > haven't seen anything like this while testing?

The effect is that we are either rendering onto the current scanout or
the next scanout is being presented with rendering unflushed.
Probably the former. Underruns have been known to have similar flicker
(at least on bdw+) but this feels more like rendering to the wrong
buffer.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre