bug#61667: 29.0.60; Failure to redisplay

[Dmitry Gutov <dgutov@yandex.ru>]

Hi Po,

Just wanted to make sure you got this email, and that it didn't get 
"hidden" by the next one.

If you have any further ideas for debugging, I'm happy to do that.

Reproducing it can still be a pain, e.g. this time around I spend a 
couple of minutes wondering whether a recent update to Xorg fixed 
everything, but then it started appearing again, with same regularity.

On 03/03/2023 15:44, Dmitry Gutov wrote:
> On 03/03/2023 02:54, Po Lu wrote:
> 
>>> So I went back to the previous Emacs versions.
>>>
>>> This MRE:
>>>
>>>    src/emacs -Q --eval "(tool-bar-mode -1)" --eval "(menu-bar-mode -1)"
>>>    --eval "(scroll-bar-mode -1)" --eval "(global-set-key \"a\" (lambda
>>>    () (interactive) (insert \"!\") (redisplay) (find-file
>>>    \"xassociations.rb\") ))" --eval "(add-hook 'find-file-hook
>>>    #'redisplay t)" --eval "(blink-cursor-mode -1 )" --eval "(setq
>>>    frame-title-format \"aaa\")"
>>>
>>>    Press 'a'. See if the buffer is displayed after a delay.
>>
>> Could you send me xassociations.rb?  I can't reproduce this with any
>> file of my own.
> 
> Attached, though this doesn't seem to depend on the exact file. E.g., I 
> reproduced this bug (indefinitely delayed refresh) just today with 
> src/alloc.c a few times.
> 
>>> --eval "(modify-frame-parameters nil '((undecorated . t)))", OTOH, we
>>>    can also cross out from the list of fixes: the problem still happens
>>>    with it, though seemingly less often (first repro at the 15th try).
>>
>> OK, thanks.  Damned blink-cursor-mode!  Does the frame still refresh
>> when you hover over the title bar buttons?
> 
> If there is a title bar, and there are buttons, yes, always.
> 
> Also, sometimes the frame refreshes right away as soon as I move the 
> mouse over its border. Sometimes, however, I can move the mouse over it 
> for a while, and refresh happens only when hovering over the title bar 
> buttons. Or over the mode-line. Or pressing some button on the keyboard, 
> of course.
> 
>> Also, since we now know blink-cursor-mode was previously screwing with
>> the results, would you please try some other window manager again and
>> see if the problem reproduces without GNOME?
> 
> Tried again with WindowMaker, couldn't reproduce there still. It's still 
> working kind of sluggishly, though. Also tried installing Xfce4, but 
> there seems to be some integration problem: it's not possible to log 
> into it from GDM (journalctl shows some errors about it trying to launch 
> its own session manager and failing because of GDM already running).
> 
> I've also tried to reproduce the error with a Lucid build of Emacs 29 
> under GNOME -- never hit the problem once.