bug#61667: 29.0.60; Failure to redisplay

[Dmitry Gutov <dgutov@yandex.ru>]

On 02/03/2023 02:34, Po Lu wrote:
> Dmitry Gutov<dgutov@yandex.ru>  writes:
> 
>> But blink-cursor-mode was on, of course. It's -Q: everything's on what
>> was not turned off.
>>
>> And it turns out to be the reason for the difference between this and
>> my personal config. With blink-cursor-mode off, the delay can reach
>> multiple seconds like I previously reported.
>>
>> Attaching new recordings with b-c-m off, same naming scheme.
>>
>> x_set_title:*scratch*  - GNU Emacs at potemkin, 565346760276
>> show_back_buffer: 565346918720
>> show_back_buffer: 565347019580
>> show_back_buffer: 565347025374
>> show_back_buffer: 565347147607
>> show_back_buffer: 565347299581
>> show_back_buffer: 565347345317
>> x_set_title: xassociations.rb - GNU Emacs at potemkin, 565347345457
>> show_back_buffer: 565347355456
>> show_back_buffer: 565353039484
>>
>> x_set_title:*scratch*  - GNU Emacs at potemkin, 565390536932
>> show_back_buffer: 565390678689
>> show_back_buffer: 565390747051
>> show_back_buffer: 565390750166
>> show_back_buffer: 565390875109
>> show_back_buffer: 565391250430
>> show_back_buffer: 565391380489
>> show_back_buffer: 565391396116
>> x_set_title: xassociations.rb - GNU Emacs at potemkin, 565391396257
>> show_back_buffer: 565391404687
>> show_back_buffer: 565397707089
>>
>> x_set_title:*scratch*  - GNU Emacs at potemkin, 565404022729
>> show_back_buffer: 565404182867
>> show_back_buffer: 565404241162
>> show_back_buffer: 565404244561
>> show_back_buffer: 565404369071
>> show_back_buffer: 565404647259
>> show_back_buffer: 565404666484
>> x_set_title: xassociations.rb - GNU Emacs at potemkin, 565404666623
>> show_back_buffer: 565404674305
>> show_back_buffer: 565405233868
> Thanks.  Unfortunately, now we're back to square one: all three logs are
> identical, and I can't see any problems in Emacs.

So... in both problematic cases is seems like there is a 
show_back_buffer call right after x_set_title, and yet it does not 
reflect on screen. Right?

And the next one (the last one) happens much later. From further 
testing, it seems to correlate to me typing 'C-x C-c', rather than to 
when the frame finally refreshes after the delay (for example, when I 
decide to stop waiting and hover with the mouse over the frame, or over 
the title bar buttons).

Does that mean, then, that the refresh of the frame after the delay does 
not correspond to any buffer flushing on Emacs' part?