Repaint Issue

[Abhijit Potnis]

On Tue, Sep 11, 2012 at 5:32 PM, Jonas Ådahl <jadahl at gmail.com> wrote:

> On Tue, Sep 11, 2012 at 1:53 PM, Pekka Paalanen <ppaalanen at gmail.com>
> wrote:
> > On Tue, 11 Sep 2012 15:44:55 +0530
> > Abhijit Potnis <abhijitpotnis at gmail.com> wrote:
> >
> >> Hello,
> >>
> >> Last few days I have been debugging a repaint issue in Weston. No
> repaint is
> >> triggered until an input event occurs or a Wayland client like
> simple-shm
> >> triggers
> >> one.
> >>
> >> Digging down, I see that struct weston_output.repaint is pointing to my
> >> output repaint
> >> function implementation. When I run weston and follow thru the logs, the
> >> repaint in
> >> my back-end implementation gets called when my
> >> 1. mouse moves/or an input event is sensed.
> >> 2. when a new client is launched.
> >> 3. when a client like simple-shm forces a repaint in a loop
> >>
> >> The intermittent screen repaints are timed long apart. So the screen
> >> doesn't get
> >> repainted until any one of the above event happens, which force a
> repaint.
> >>
> >> http://www.youtube.com/watch?v=VGZoFZ9MQX8&feature=youtu.be
> >>
> >> Here is a video of the behaviour. I launch simple-shm and then kill it
> >> (time 0:05), the
> >> screen isn't updated until I move my mouse (time 0:11). When I move the
> >> mouse the
> >> screen is updated and the residual simple-shm disappears from the
> screen,
> >> which is
> >> actually a repaint.
> >>
> >> Does any body else happen to see such behaviour ?
> >
> > Yeah, I've seen similar issues on the DRM and X11 backends. When I
> > launch an app by clicking a button in the panel, the new window does not
> > appear, until something else causes a repaint. Weston-terminal and
> > flower, at least.
>

The repaint problem is only when a client is killed, but not when it is
launched.
The launch process does behave as expected (as of now :-)) .

>
> > Repaint is supposed to be as-needed only, not periodical, but clearly
> > some trigger is missing. Maybe a new surface is not assigned an output
> > until redraw, and redraw does not happen until there is damage, and
> > damage is not applied, if the window is not mapped? Or something like
> > that, chicken-and-egg problem with assigning an output. A wild guess...
> >
>

Ya, I too feel so. I see that the final weston_output_finish_frame() call
after
 a client is killed arrives with output->repaint_needed set to 0, and hence
 weston_output_repaint is not called. How does the window unmap-ing
process occur ? Is this expected ?


> I've seen this for popup surfaces as well. It's fixed by strategically
> adding a call to the update transform function which will set the
> bounding box, which then will trigger assign_output to work properly.
> I have a patch fixing my case that I haven't sent yet and it's
> possible that it's the same issue with non-popup surfaces.
>

Would be good to have :-)


>
> Jonas
>

@Ander: Ya, I am writing a GLES2 over fb back-end for a specific board. And
I haven't modified any of the client code provided in the Weston repo. The
are
compiled and run as is.

Thanks for the answers.

-- 
Regards,
Abhijit Potnis
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