Re: Strange screen blanking behavior with HDMI switch

On Fri, 21 Jun 2024, Aryeh Friedman wrote:

> I have a 3 to 1 HDMI switch (3 inputs to one output) and sometimes
> (about 10% of the time) when the screen blanker/screen saver kicks in
> (power save mode) the switch thinks the input actually turned off and
> goes to another one.

Switching is pretty normal, my display does the same when one of
the input is blank, which is sometimes annoying. Sometimes
I just turn off DPMS for a while (xset -dpms).
You can also turn off the display immediately with "xset dpms force off".

I don't think that enabling a screen saver (something is displayed
on the screen all the time) counts as "power save" or "standby".

> switch back the resolution has been reset to
> 3840x2160 from my preferred 2560x1440

First, I would recommend trying things without the HDMI switch
in between if possible to rule out this component (or not).

If I understand correctly, you do not like 3840x2160 mode
being offered by the screen.

Xorg server with "-verbose 5" should give you the list
of available and detected modes in the log, I don't
know how to disable certain modes in the config,
but you can certainly try some fixed mode
in the configuration. Maybe "xrandr --rmmode" can do the
right thing.

Some XFCE4 specific info from 2018: https://askubuntu.com/a/1054199

Marcin