bug#61667: 29.0.60; Failure to redisplay

[Dmitry Gutov]

On 27/02/2023 12:30, Gregory Heytings wrote:
> > I redid the screencast using ffmpeg and x11grab, and it captures the 
> > problem fine. See the last two attempts (out of 6) in this video:
> >
> > https://a.uguu.se/PThfScNL.webm
> >
> > Note I also added (insert "!") and (redisplay) so that it's easy to 
> > see the exact moment "a" was pressed.
>
> Thanks!  After seeing this, I'm now convinced that the problem is not a 
> GNOME one, for two reasons:
>
> 1.  The effect of (insert "!") (redisplay) is immediately visible on 
> screen.  Why would GNOME treat the effect of changing the buffer from 
> *scratch* to xassociations.rb differently?
>
> 2. The delay is different with emacs -Q (13 frames in that video, which 
> at 25 FPS means 520 ms) and with your config.  Why would GNOME treat the 
> same app differently depending on how it is configured?

Thank you. At the very least it seems to mean that Mutter isn't outright 
broken.

There seems to be some problem regarding synchronization around the 
setting of the frame title.

One of the sides is subtly wrong -- not sure which one -- but other 
applications don't seem to exhibit the same buffering problem, so some 
sequence of action which would fix our situation should exist.