[PATCH weston] xwm: fix intermittent half-drawn decorations problem

[Pekka Paalanen]

On Tue, 17 Jan 2017 17:42:37 +0000
Emmanuel Gil Peyrot <emmanuel.peyrot at collabora.com> wrote:

> Hi,
> 
> On Tue, Jan 17, 2017 at 05:33:20PM +0200, Pekka Paalanen wrote:
> > From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > 
> > To reproduce the problem:
> > - start weston (x11 backend worked, glamor in Xwayland makes no
> >   difference)
> > - start xterm
> > - very very slowly move the pointer in the xterm decorations onto or
> >   away from a button
> > - the moment the decorations are updated, they will appear incomplete,
> >   e.g. completely without buttons and title text
> > - if you cause just one more pointer motion event, the decorations will
> >   update to completely drawn appearance
> > 
> > Another way to reproduce the problem is to have an xterm and change its
> > window title. This is easy if you use a shell prompt that updates the
> > terminal window title. When the title updates, decorations will be
> > half-drawn until something happens in XWM.
> > 
> > The fix: flush.
> > 
> > Apparently the drawing commands did not get flushed to the X server
> > until any other X11 action pushed them through.
> > 
> > xcb_flush() is the real fix here. cairo_surface_flush() is added just
> > for good measure, because documentation indicates it would be better
> > used, however it was not strictly necessary to fix the problem in my
> > experiments.
> > 
> > Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>  
> 
> I tried dolphin-emu which was affected by this problem due to changing
> its title to display the current performances of the emulation, and
> this fixes it.  Thanks!
> 
> Tested-by: Emmanuel Gil Peyrot <emmanuel.peyrot at collabora.com>
> Reviewed-by: Emmanuel Gil Peyrot <emmanuel.peyrot at collabora.com>

Pushed:
   6d3887b..db7b9f3  master -> master


Thanks,
pq
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