On 6/2/22 09:08, stan via users wrote:
> On Wed, 1 Jun 2022 10:54:50 -0400
> Fulko Hew<fulko.hew@gmail.com>  wrote:
>
>> I just had it again, it's very rare.
>> And it's happened over the last number of Fedora versions (-1 to -n)
>>
>> If I come back to use my computer and hit a key at exactly the same
>> time as the screen decides to blank (I don't use screensavers) then
>> the screen does blank, but no key or mouse activity (I've tried) will
>> cause the screen to wake up again.  I know the machine is still
>> active because one of the keystrokes I tried, woke up and started to
>> play a Youtube video that was paused on one of my browser instances.
>>
>> So everything is still working, but nothing (I've found) will
>> un-blank the screen.
>>
>> Idea's anyone?
>>
>> [It's hard to replicate, but I seem to be able to time it right/wrong
>> every few months.]
> What you describe is being caused by a race condition of some kind.
> The screensaver is not using locks to ensure atomic actions.  So, two
> events are occurring at roughly the same time, and depending on which
> one wins the race, the screen recovers or thinks it is already
> recovered, even though it is blank [blank loses the race].  You could
> open a bugzilla against the screensaver, just so they are aware of the
> issue. It probably won't get fixed on its own, but if they are in the
> code anyway for something else, they might look at this too, if they
> know about it.
>
> Have you tried switching to a virtual console, Ctl-Alt-F[3-6]?
> That should trigger a context switch to the framebuffer driver, which
> refreshes the monitor. Then, if you switch back to the gui, usually
> Ctl-Alt-F1, the context switch back to the desktop should initialize
> things properly, because it thinks it is already active.  Worth a
> try, but no guarantees.  The virtual consoles have been losing
> functionality [1] as fewer and fewer developers use them, and recently
> started using simplefb from the kernel, so I'm not sure if that might
> not short circuit any context switching.
>
> 1.  The latest was losing the scrollback buffer.  That meant that
> screen lost its scrollback as well.  I really miss it, any one know of a
> user space replacement, I'm tired of typing ' | less' after everything,
> the second time, when things scroll off the screen the first time.  :-)
> Searching hasn't turned up a viable alternative.
> _______________________________________________
Can use pkill, pgrep to query and restart the gui from the virtual console.