Eyal Lebedinsky (HE12026-02-05):

Me too. I use fedora and have the same issue. Actually, using a KVM to switch to another machine
then back does the same thing (dark screen, monitor says no HDMI signal). I ended up with the same solution (xrandr).
BTW, the text consoles (ttyN) are visible, only the X11 one (tty1 for me) is blank.

For me this started a few months ago, it was working fine until then.

I agree that X11 seems to think all is well.

I suspected it is the intel embedded GPU that is at fault, the vibe on the 'net is that this driver is in bad shape.
Changing X11 to use modesetting (was intel) did not help.

Thanks for confirming I am not alone having the issue.

I have written the following script (that you can consider public
domain), to be called from the greeter-wrapper. At first I considered
calling `xrandr --output $out --primary --auto` but I eventually decided
to kill the greeter wrapper and cause it to restart. Among other things
because greeter-setup-script creates a background image at the
resolution of the screen.

Regards,

--
Nicolas George


#!/bin/zsh

if [[ $(</proc/$PPID/cmdline) != *wrapper*greeter* ]] ; then
print -u2 "Must be started from greeter wrapper"
exit 1
fi

restart=false
while true ; do
xrandr=$(xrandr --current)
xrandr=(${(f)xrandr})
xrandr=(${(M)xrandr:#* connected *})
if [[ $#xrandr != 0 ]] ; then
break
fi
restart=true
xev -root -event randr |
while read -r ev det ; do
if [[ $ev == RRScreenChangeNotify ]] ; then
break
fi
done
done
if [[ $restart == true ]] ; then
kill $PPID
fi

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 14/2/26 00:26, Nicolas George wrote:

Eyal Lebedinsky (HE12026-02-05):

Me too. I use fedora and have the same issue. Actually, using a KVM to switch to another machine
then back does the same thing (dark screen, monitor says no HDMI signal). I ended up with the same solution (xrandr).
BTW, the text consoles (ttyN) are visible, only the X11 one (tty1 for me) is blank.

For me this started a few months ago, it was working fine until then.

I agree that X11 seems to think all is well.

I suspected it is the intel embedded GPU that is at fault, the vibe on the 'net is that this driver is in bad shape.
Changing X11 to use modesetting (was intel) did not help.

Thanks for confirming I am not alone having the issue.

I have written the following script (that you can consider public
domain), to be called from the greeter-wrapper. At first I considered
calling `xrandr --output $out --primary --auto` but I eventually decided
to kill the greeter wrapper and cause it to restart. Among other things because greeter-setup-script creates a background image at the
resolution of the screen.

Probably similar to my script (I do not use/understand zsh).
However, how do you launch it if the screen goes blank while being used, like unplug/plug the monitor?

My script is similar but launched from cli.
I need to find a way to assign a "hot key" to launch the script blind, regardless of the program that has focus.

--
Eyal at Home (eyal@eyal.emu.id.au)

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-02-13, Eyal Lebedinsky <eyal@eyal.emu.id.au> wrote:

On 14/2/26 00:26, Nicolas George wrote:

Eyal Lebedinsky (HE12026-02-05):

Me too. I use fedora and have the same issue. Actually, using a KVM to switch to another machine
then back does the same thing (dark screen, monitor says no HDMI signal). I ended up with the same solution (xrandr).
BTW, the text consoles (ttyN) are visible, only the X11 one (tty1 for me) is blank.

For me this started a few months ago, it was working fine until then.

I agree that X11 seems to think all is well.

I suspected it is the intel embedded GPU that is at fault, the vibe on the 'net is that this driver is in bad shape.
Changing X11 to use modesetting (was intel) did not help.

Thanks for confirming I am not alone having the issue.

I have written the following script (that you can consider public
domain), to be called from the greeter-wrapper. At first I considered
calling `xrandr --output $out --primary --auto` but I eventually decided
to kill the greeter wrapper and cause it to restart. Among other things
because greeter-setup-script creates a background image at the
resolution of the screen.

Probably similar to my script (I do not use/understand zsh).
However, how do you launch it if the screen goes blank while being used, like unplug/plug the monitor?

My script is similar but launched from cli.
I need to find a way to assign a "hot key" to launch the script blind, regardless of the program that has focus.

I didn't notice this thread. I use lightdm and sometimes my screen
powers off completely rather than going into power-saving mode. I then
have to unplug the monitor for 30 seconds or so to get it working again.

I always thought it was a BIOS/ACPI bug on my old ACER X1301.

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Eyal Lebedinsky (HE12026-02-14):

However, how do you launch it if the screen goes blank while being
used, like unplug/plug the monitor?

That is not the kind of script one launches manually, it is meant to be
started automatically, as I said:

to be called from the greeter-wrapper.

But there are multiple ways of running commands in these circumstances, starting with the obvious ones: switching to a text console or
connecting from the network.

Regards,

--
Nicolas George

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Bigsy Bohr (HE12026-02-14):

I didn't notice this thread. I use lightdm and sometimes my screen
powers off completely rather than going into power-saving mode. I then
have to unplug the monitor for 30 seconds or so to get it working again.

I always thought it was a BIOS/ACPI bug on my old ACER X1301.

It probably is. At the very least it has nothing to do with the issue I reported here.

Regards,

--
Nicolas George

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 16/2/26 06:40, Nicolas George wrote:

Eyal Lebedinsky (HE12026-02-14):

However, how do you launch it if the screen goes blank while being
used, like unplug/plug the monitor?

That is not the kind of script one launches manually, it is meant to be started automatically, as I said:

to be called from the greeter-wrapper.

Understood, but as I see the problem
- it is not related to a login
- it started a few months ago, probably due to some update (but I use fedora so YMMV). So not a BIOS issue.

It will be good to understand the core issue. Maybe a udev rule stopped working?
$ xrandr --listmonitors
says, after the monitor is reconnected,
Monitors: 0
Who/what should add the monitor to the list when it is detected?

But there are multiple ways of running commands in these circumstances, starting with the obvious ones: switching to a text console or
connecting from the network.

"switching to a text console" works, but requires a login...
I did not try "connecting from the network", but again it requires more setup. Don't know if xrandr will work.

I leave one xterm window in focus before switching the monitor away (KVM) then, when reconnected, run (blind) my script (called 'x').

Regards,

--
Eyal at Home (eyal@eyal.emu.id.au)

--- PyGate Linux v1.5.11
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)