bug#28589: 27.0.50; Emacs screen often becomes blank

bug#28589: 27.0.50; Emacs screen often becomes blank

[Katsumi Yamaoka]

Hi,

Emacs screen often becomes blank or blinks.  This didn't happen
the last weekend, doesn't happen sometimes but often happens.
Changing the window configuration --- scrolling a window, showing
a message of two or more lines in the echo area, etc. --- seems
to cause it.  More funny thing is, when two Emacsen are running,
the one of which the frame is not selected becomes blank.
Typing any key in the selected blank frame will help, as if
(sit-for ∞) is running.

Thanks.

In GNU Emacs 27.0.50 (build 1, i686-pc-cygwin, GTK+ Version 3.18.9)
 of 2017-09-25 built on localhost
Windowing system distributor 'The Cygwin/X Project', version 11.0.11900000

bug#28589: 27.0.50; Emacs screen often becomes blank

[Katsumi Yamaoka]

On Mon, 25 Sep 2017 10:01:30 +0900, Katsumi Yamaoka wrote:
> Emacs screen often becomes blank or blinks.  This didn't happen
> the last weekend, doesn't happen sometimes but often happens.
> Changing the window configuration --- scrolling a window, showing
> a message of two or more lines in the echo area, etc. --- seems
> to cause it.  More funny thing is, when two Emacsen are running,
> the one of which the frame is not selected becomes blank.
> Typing any key in the selected blank frame will help, as if
> (sit-for ∞) is running.

Reverting the change c0af83b[1] solves this problem.

[1]
Don't attempt to disable double buffering in newer GTK+ versions
<http://lists.gnu.org/archive/html/emacs-diffs/2017-09/msg00293.html>

> Thanks.

In GNU Emacs 27.0.50 (build 4, i686-pc-cygwin, GTK+ Version 3.18.9)
 of 2017-09-26 built on localhost
Windowing system distributor 'The Cygwin/X Project', version 11.0.11900000

bug#28589: 27.0.50; Emacs screen often becomes blank

[Philipp Stephani]

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Katsumi Yamaoka <yamaoka@jpl.org> schrieb am Di., 26. Sep. 2017 um
06:44 Uhr:

> On Mon, 25 Sep 2017 10:01:30 +0900, Katsumi Yamaoka wrote:
> > Emacs screen often becomes blank or blinks.  This didn't happen
> > the last weekend, doesn't happen sometimes but often happens.
> > Changing the window configuration --- scrolling a window, showing
> > a message of two or more lines in the echo area, etc. --- seems
> > to cause it.  More funny thing is, when two Emacsen are running,
> > the one of which the frame is not selected becomes blank.
> > Typing any key in the selected blank frame will help, as if
> > (sit-for ∞) is running.
>
> Reverting the change c0af83b[1] solves this problem.
>
> [1]
> Don't attempt to disable double buffering in newer GTK+ versions
> <http://lists.gnu.org/archive/html/emacs-diffs/2017-09/msg00293.html>
>
>
Sigh, I had almost expected this would happen. Reverted with 2fa19cc551.
But now we have another time bomb in the codebase:
the gtk_widget_set_double_buffered function is deprecated and will probably
be removed sometime. This makes the migration to a pure GTK+ build even
more pressing.

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bug#28589: 27.0.50; Emacs screen often becomes blank

[martin rudalics]

 > Sigh, I had almost expected this would happen. Reverted with 2fa19cc551.
 > But now we have another time bomb in the codebase:
 > the gtk_widget_set_double_buffered function is deprecated and will probably
 > be removed sometime. This makes the migration to a pure GTK+ build even
 > more pressing.

Looks like the decisive blow, indeed.  Admittedly, inhibiting double
buffering was a gross hack too.  But I doubt Jan had any alternative
solutions at hand when he coded that.

Do I understand correctly that the entire effect of setting double
buffering off is encapsuled in the case where a GDK_EXPOSE event is
handled?

martin