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Re: Screen randomly wakes up from standby / energy saving mode



On Saturday, March 20, 2021 12:46:00 PM CET Daniel Schröter wrote:
> inkbottle schrieb am Mittwoch, 26. Februar 2020 um 17:20:03 UTC+1:
> > My screen randomly wakes up from standby
> 
> I have the same problem. It seems to happen since one oft the last upgrades.
> I'm running KDE from unstable (5.20.5).
> 
> One monitor went to sleep (and stands there) fine. The other monitor wakes
> up every minute. No logs in journalctl or dbus-monitor.
> 
> I also tried it with a new profile (other user). I already replaced the
> displayport cable.
> 
> In sddm it works fine. But if I start "real" KDE it wakes up every minute
> randomly.
> 
> If I do
> xrandr --output DP-1 --off
> the monitor went to sleep and stays in sleep mode. After KDE(?) sends sleep
> to the monitor (after 10 minutes inactivity) the problematic monitor wakes
> up from sleep again :-(
> 
> Any ideas to debug this?

Your analysis of KDE waking up the monitor by sending a sleep signal is 
interesting. (I don't know how you figured that out.)

At one point I understood that `dpms` was buggy. That `kwin` had difficulties 
communicating with `dmps` for intrinsic reasons, and that it will never be 
fixed anyway, nor even investigated, because `xorg` isn't developed any longer. 
I don't remember what exactly made me believe that in the first place.

Consequently I endeavored to see what could be done with `wayland`.

I found out that a command that shows how the kernel see the monitor, 
`drm_info`, invariably returns correct information, unless `kwin` is running, 
in which case those data became preposterous, wrong. Just as if it is the 
whole `kwin` stake that might have issues. Again it is the layman view, I'm 
probably completely mistaken. However it does work quite all right with gnome/
wayland if I remember correctly.

Here, what I found about that at the time:
https://bugs.kde.org/show_bug.cgi?id=404092
(I'm not sure nobody ever read what I wrote. They must have a lot on their 
plate.)

At one point I did use that sort of command:
`while true; do xset dpms 10 10 10; sleep 10; xset dpms force off; sleep 600; 
done`

But it wasn't working very well neither, as if something was messing around 
with it in the background, and even though it did seem bullet proof, the 
monitor always manage to wake up now and then, only for a short time, which 
was resulting in a sort of very slow flickering, not sure it's good for the 
monitor.

Sooo, what I do now: I turn the computer off!

Oh, yes, turning the monitor off wouldn't do it, it would put such a mess, it'd 
take me like 30 min, to fix it when turning it back on.


> 
> Bye





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