Display powersave only blanks, but does not turn off

[Florian Echtler]

[ Impact ]

On some machines when the screen blanks, the LCD backlight stays on.

[ Workarounds (reported to work by some people) ]

* Configure the monitor (in its own menus) to not auto-switch inputs.
* Change from HDMI to DisplayPort cables.
* Disable HDMI audio output.

[ Test Plan ]

0. Make sure you're using an LCD (not OLED) so you can see if the backlight is on.
1. In Settings -> Power -> Screen Blank, set the inactivity period to 1 minute.
2. Verify after 1 minute that the screen is blank and the backlight is also visibly off.

[ Where problems could occur ]

[ Other Info ]

[Sebastien Bacher (seb128)]

Thank you for your bug report. Could you do
$ apport-collect 1971434

do you use an xorg or wayland session and with which videodriver?

[Florian Echtler (floe)]

apport information

[Florian Echtler (floe)]

apport information

[Florian Echtler (floe)]

apport information

[Florian Echtler (floe)]

I'm using Xorg 2:21.1.3-2ubuntu2, with kms on "Intel Iris Plus Graphics (G7)". Xorg.0.log attached as well.

[Florian Echtler (floe)]

One extra observation: when I use "xset dpms force off" to send the display to sleep, it stays in sleep indefinitely until the next user input, so apparently g-s-d never touches the power state.

[Payam Nab (papampi)]

Having same issue on Xorg with Nvidia-driver-510.

[Tim (timw-suqld)]

Same issue on 22.04 Gnome Wayland session, Nouveau driver on a Geforce MX450 (Iris Xe Graphics onboard using i915 driver)

Fixed for me by moving to the nvidia proprietary driver

[aurelijusr (aurelijus-rozenas)]

Same on 22.04 Gnome Xorg, Nouveau driver on a GeForce GTX 1650 Ti Mobile

[David Palacio (davplsm)]

I had the same issue after upgrading to ubuntu 22.04 and the logs showed the following error.

Failed to connect to the screen saver: Error al llamar StartSereviceByName para org.gnome.ScreenSaver: Failed to execute program org.gnome.ScreenSaver: No such file or directory

The missing file was /usr/bin/gjs which I was able to solve by installing the gjs package. After restarting session the display powered off as espected.

I hope your problem is the same and you can solve it.

[ed20900 (ed20900)]

I'm on Wayland and I have the same problem. Ubuntu 22.04 upgraded from Ubuntu 20.04.

[uunicorn (uunicorn)]

Yep, installing gjs fixed the problem for me too: https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1971434/comments/10

It also fixed the problem with custom keyboard shortcuts.

[Cas (calumlind)]

I am facing the same issue since upgrading from 20.04 to 22.04.

I have a Lenovo ThinkPad X1 Extreme Gen 3 with an external monitor (Dell P2720DC) connected via USB-C displayport that used to turn off completely but now only blanks with the backlight remaining on.

Display server: X11
Display driver: Nvidia 510.85.02

`xset dpms force off` turns off monitor correctly
gjs is already installed

Any help with debugging this would be useful since I don't see any issues in journalctl

I still need to test if Nvidia Prime profile has any effect (performance vs on-demand) or if same occurs under Wayland.

[gazhay (gazhay)]

Same issue, GJS already installed.

22.04 LTS
X11
Nvidia 515

[Eric Slimko (slim0287)]

I have the same issue.

22.04 LTS (though Pop!_OS 22.04)
Display server: X11
Display driver: Nvidia 515.48.07

gjs is already installed.

OS is installed on an iMac 14,2 from late 2013 (not dual boot, Linux is the sole operating system)

‘xset dpms force off’ does not turn off the monitor, it just blanks the screen.

[gazhay (gazhay)]

I am finding that display does turn off (following the fade to black) but within 20 to 30s the monitors turn back on and either remain on fully or just blank after a period of time but still powered.

Not convinced this is gnome-settings related and maybe this bug is in the wrong place?

[gazhay (gazhay)]

More appropriate project

[Romano Giannetti (romano-giannetti)]

Adding data: there is something, probably lingering after the upgrade, that resets the `xdpm` data of the X server. After a while the screen starts to go off after very little inactivity, *without* enabling the screensaver (I blindy wrote my password in a couple of mails ;-)...).

If I set:

    xset dpms 600 600 600

it seems to work, is confirmed by `xset q`, but after a while (much less than 10 minutes) the screen goes off and when touching a key and checking, `xset` says:

$ xset q
[...]
DPMS (Energy Star):
  Standby: 0 Suspend: 0 Off: 0
  DPMS is Enabled
  Monitor is On

The only workaround I found is to completely disable dpms with `xset -dpms`; with tha the screensaver kicks-in correctly but then the display will never shut off...

[Marc Deslauriers (mdeslaur)]

gnome-screensaver is definitely the wrong package.

[Hany Said EL-Nokaly (hany-elnokaly)]

Same issue. Apparently as many other bugs, Canonical will not fix it and we have to wait until next LTS release.

[Philipp Wendler (philw85)]

Sane issue here, but somewhat different setup than mentioned so far and more details:

- Ubuntu 22.04 with latest updates (Linux 5.15.0-48-generic, gnome-shell 42.4-0ubuntu0.22.04.1, mutter 42.2-0ubuntu1)
- gjs is installed
- occurs on both Wayland and X11
- amdgpu (AMD Ryzen 5 IGP)
- all Gnome extensions disabled except for standard extensions
- Problem exists even if I lock the screen immediately after logging in on a fresh session with no applications running except for a terminal.
- Problem exists also on the login screen if no user is logged in at all.
- When using an X11 session, "xset dpms force off" does not turn off the monitor.
- Back on 20.04, the screen successfully turned off under X11.

Log from "journalctl --user" covering the period of locking screen and logging in again a few minutes later:

Sep 22 10:41:48 server.passau systemd[42825]: Started Application launched by gnome-session-binary.
Sep 22 10:41:48 server.passau systemd[42825]: Started Application launched by gnome-session-binary.
Sep 22 10:41:50 server.passau pkexec[44266]: pam_unix(polkit-1:session): session opened for user root(uid=0) by (uid=1000)
Sep 22 10:41:50 server.passau update-notifier.desktop[44272]: [90B blob data]
Sep 22 10:41:50 server.passau update-notifier[44238]: gtk_widget_get_scale_factor: assertion 'GTK_IS_WIDGET (widget)' failed
Sep 22 10:41:50 server.passau update-notifier[44238]: gtk_widget_get_scale_factor: assertion 'GTK_IS_WIDGET (widget)' failed
Sep 22 10:41:50 server.passau update-notifier.desktop[44272]: [163B blob data]
Sep 22 10:41:50 server.passau update-notifier.desktop[44272]: [101B blob data]
Sep 22 10:47:10 server.passau gnome-shell[42972]: JS ERROR: Failed to initialize fprintd service: Gio.DBusError: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name net.reactivated.Fprint was not provided by any .service files
                                                  asyncCallback@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:114:23

Log from "journalctl --system" covering the same period (I removed networking-related log messages from SSH and systemd-networkd):

Sep 22 10:41:18 server.passau systemd[1]: systemd-hostnamed.service: Deactivated successfully.
Sep 22 10:41:18 server.passau systemd[1]: systemd-localed.service: Deactivated successfully.
Sep 22 10:41:43 server.passau rtkit-daemon[1875]: Supervising 5 threads of 3 processes of 1 users.
Sep 22 10:41:43 server.passau rtkit-daemon[1875]: Successfully made thread 44232 of process 42835 owned by '1000' RT at priority 5.
Sep 22 10:41:43 server.passau rtkit-daemon[1875]: Supervising 6 threads of 3 processes of 1 users.
Sep 22 10:41:47 server.passau geoclue[43043]: Service not used for 60 seconds. Shutting down..
Sep 22 10:41:47 server.passau systemd[1]: geoclue.service: Deactivated successfully.
Sep 22 10:41:50 server.passau pkexec[44266]: philipp: Executing command [USER=root] [TTY=unknown] [CWD=/home/philipp] [COMMAND=/usr/lib/update-notifier/package-system-locked]
Sep 22 10:47:14 server.passau gdm-password][44332]: gkr-pam: unlocked login keyring

If there is anything I can do to help debug this, I am glad to assist. If desired, I can also upload data with...

[gazhay (gazhay)]

Can confirm #18 - same results here.

The only solution I have found so far is to run a script via crontab.
Check to see if monitor should be off "xset -q" looking for "Monitor is off"

If it is supposed to be off call
"xset dpms force suspend
sleep 2
xset dpms force off
"

This seems to get the monitors into standby mode - just forcing the off did not work for me - ymmv

This is an inelegant hack but it now means the monitors spend more time asleep than on which is progress.

This definitely isn't gnome-settings-daemon related but perhaps I wrongly assumed gnome-screensaver was what handled display sleep - this won't get the attention it needs here though.

[Richard Brown (hypromangt)]

I have the same issue, migrating from 20.04 to 22.04.1 (worked fine on 20.04)
Asus N56VM laptop with a GeForce GT 630M

"xset dpms force off" will turn the display off properly.

Unfortunately, the cron approach described in #22 doesn't work on my system; when the screen blanks after inactivity, xset -q still reports that the "Monitor is On".

[edit: appended]
I came up with another hack/workaround that does work on my machine. The idea is to read the Settings->Power->"Screen Blank" idle timeout value from Gnome and use it to sync the DPMS timeout value using xset. I have this script running periodically via cron:

---- code snippet START ----
#!/usr/bin/env bash

IDLE_MINUTES=$(gsettings get org.gnome.desktop.session idle-delay | cut -d ' ' -f2)
X11_DISPLAY=:1
if [ -e "${HOME}/.X11_display" ]; then
    X11_DISPLAY=$(cat "$HOME/.X11_display")
fi
DISPLAY=${X11_DISPLAY} xset dpms 0 0 $IDLE_MINUTES
---- code snippet END ----

Setting DISPLAY is needed; otherwise xset can't interact with the X server. To achieve this, I've added the following code to my ~/.bashrc file:

---- code snippet START ----
# Record the X11 DISPLAY value if available
if [[ -n "${DISPLAY}" ]] && [[ ${DISPLAY} =~ ^:.* ]]; then
    echo "${DISPLAY}" > "${HOME}/.X11_display"
fi
---- code snippet END ----

Not perfect by any stretch, but better than a dark + backlit LCD screen.

[Florian Echtler (floe)]

One more datapoint: I noticed that this issue can be worked around for me when I manually lock the screen at least once using the Super-L hotkey. Before, the screens only blanked but didn't turn off; afterwards, they properly go into powersave.

[Christopher Franz (hydraulic)]

So this doesn't go down any dead-ends...

I have encountered this on:
20.04, both XFCE4 and GNOME
22.04, XFCE4

Using X11

When installed as a DE on Ubuntu Server, XFCE4 brings in a ton of GNOME deps so that may be covering the same territory. Xubuntu spin behaves similarly. I did -not-, however, experience it on a Kubuntu spin (all of the above were on the same hardware). Curious if that means all roads lead to GNOME (lol sorry!)

I see a prevalence of Nvidia users whenever I research this issue but in my case it's an AMD card on an AMD board, so we can cross that off as a vector (using AMDGPU in the kernel, none of the proprietary Pro stuff).

Leaving out blanking entirely has no effect; neither does disabling the DE power management and replacing it with XScreensaver. `xset -q` reports enabled and working, `xset dpms` will enable and disable as expected.

HTH

[Kevin Milner (kevinmilner)]

Not sure if related, but posting in case helpful to others who find this ticket.

I had an issue with the screen not going to sleep after upgrading from 20.04 to 22.04 and found this ticket. In my case, the screen wasn't blank but instead the gnome lock screen would stay on. I found that changing the "screen blank" time in settings did the trick. It was set to 15m and would lock but not blank (nor actually turn off the display); I changed the setting to 12m and then back to 15m and now it works again. Maybe some sort of issue in migrating settings on upgrade?

[mbosi (mathieu-bosi)]

I was having the very same problem.

The only (partial) workaround that worked for me was to delete the default "Super + L" lock-screen shortcut and replace it with a custom one using the same key combination and setting as command:

bash -c 'sleep 0.1 && xdg-screensaver lock && xset dpms force off'

This is based on these answers:
- Screen turns on automatically (xset dpms force off): https://unix.stackexchange.com/a/720365
- Setting custom shortcuts: https://help.ubuntu.com/stable/ubuntu-help/keyboard-shortcuts-set.html.en

Maybe the fact that a delay is necessary before of calling the `xset dpms force off` command might give some hint about why the bug might occur in the first place.

Now, the only missing part would be how to automate this same command after a given inactivity time, in a not too clunky way ...

Regards.

[zezba9000 (zezba9000)]

I have the same bug (and another I noticed looking into this).

* Ubuntu 22.04.2 LTS
* Processor: "AMD® Ryzen 7 7735hs with radeon graphics × 16"
* Graphics: "REMBRANDT (rembrandt, LLVM 15.0.6, DRM 3.47, 5.19.0-40-generic)"
* System: Minisforum UM773 Lite

So whats odd is I logged in with Wayland (I'm 100% sure of this).
However when I opened about in Ubuntu settings it said I was in X11.
So I logged out then back in again and now I'm on Wayland.

Ignoring the login bug, X11 seems to have this issue while Wayland does not.

[Sadaharu Wakisaka (psw1747)]

When I select "Power Saver" to 'Power Saving' mode, the display(s) turn off.
When I select "Power Saver" to 'Performance' mode, they don't.

Ubuntu 22.04 upgrade from 20.04. Optiplex 5090 i7-11700 Gnome/X.org
Ubuntu 20.04 doesn't have this bug.

[T (reguluss)]

Still have this problem on Ubuntu 22.04.2 LTS (i7-12700).

Both Wayland and X11 tried, no different.
gjs already installed.
Also tried to slected "Power Saver" to 'Power Saving' mode as [#30](https://bugs.launchpad.net/gnome-settings-daemon/+bug/1971434/comments/30) said, not work for me.

Also tried `xset dpms force off/standby`, the monitor goes off (really off not dark screen) but light again few seconds later. I didn't find any background process wake screen up (it's a new installed Unbuntu, only autossh/openssh running, not related).

other similar issue reports:
https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1998716
https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1975557

[Force (force000)]

I have the same issue, even with gjs installed and tried the other suggestions in this report.

I did upgrade from 21.10 (I think?) to 22.04. Even after a clean install with restoring the home folder, I still have the same problem.

[Daniel van Vugt (vanvugt)]

If you're using 22.04 then please try adding:

  MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0

to /etc/environment and then rebooting.

[David Beswick (dlbeswick)]

Hello Daniel, I'm on 22.04, I can confirm that adding the config in your #33 fixes the issue for me. I have Ryzen graphics.

Prior to the fix, running "xset dpms force off" resulted in the screen turning off and then turning on after a couple of seconds. After the fix, the screen stays off until input is entered, and the screensaver does turn off the monitor as expected.

[JackyMatt (imyhxy)]

I have confirmed that #33 method not working on Ubuntu 23.04.

[Manel R. Doménech (manelio)]

Ubuntu 23.04 with Intel Iris Xe Graphics. Same problem. Really annoying since my monitor doesn't hava a power button.

[JackyMatt (imyhxy)]

Yes, same configurations as #36 and same issue.

[Dawn Smith (desm1th)]

I'm on 22.04 and can also confirm that the fix in #33 worked for me. Thanks for the help Daniel!

[JackyMatt (imyhxy)]

Anyone has any idea what is going on here?

[Philipp Wendler (philw85)]

MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0 from #33 also does not help here. Ubuntu 22.04, latest updates, kernel 6.2.0-35-generic, Wayland, integrated AMD GPU (more details about system in #21).

[Razvan Matei Dedu (n6v26r)]

The AtomicKms workaround did it for me. I'm on Manjaro gnome 45.

[Sam Vervaeck (samvv)]

For me the correct description of the bug was most likely given in [1].

When I use my laptop's screen, everything works fine. When I am using a Philips 275E UHD display, the behavior described in this thread appears.

Chances are that the KMS driver is doing something wrong.

I couldn't find an item on the Linux Kernel mailing list that addresses this (though it has been difficult to search). If someone knows more about how to debug this and file an issue, I'm all ears.

[1]: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1998716/comments/18

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1971434

[Force (force000)]

The MUTTER_DEBUG_ENABLE_ATOMIC_KMS worked for me as well, thank you!

/edit: Unfortunately it stopped working again

[Tim Richardson (tim-richardson)]

I use the wayland session. I sort of have this bug. The screens do power off, but then the backlights resume. It is still a blank screen
Update: this happened after I added a new monitor, a Lenovo ThinkVision, using HDMI. Swapping the connection to display port eliminated the problem

[JackyMatt (imyhxy)]

This bug is annoy.

I have test on Ubuntu 20.04, 22.04, 23.04, 24.04. All of them have the same bug on my machine.
And I also have tested on the HDMI and Display port on the motherboard side.

And when I switch to LightDM, the monitor can turn off but the lock screen shortcut won't work and I don't like LightDM very much.

My machine is i3-13700K on a Z790-PLUS motherboard, and no GPU.

[Michał Fita (michal.fita)]

This is Gnome bug I presume that manifests mostly on Ubuntu (clash with Canonical's tweaks) with some HDMI monitors (mostly Lenovo). The same monitors work as intended under Windows.

My bet is they send some message back to the computer when they change power state after requested to go to full power save. That in exchange wakes up the system, which ten keeps the screen blank, but backlight don't go off; they don't go off on both screens. If I turn off my Lenovo with switch, the laptop screen finally turns off after some time, but not always.

[JackyMatt (imyhxy)]

I can confirm with #47, I have dual system on the same machine, Windows is works without issue, and Ubuntu does have.

My monitor is HDMI but not Lenovo.

[Daniel van Vugt (vanvugt)]

Yes I too have believed for years there must be a feedback problem causing this. The reason it's still not fixed is just that it's so rare... every time I try to debug it the problem doesn't happen at all.

[JackyMatt (imyhxy)]

We should solve this issue before Earth Day. It has caused a lot of wastage of electricity.

[Ilya B. (citrus22)]

I have this bug since 23.10. After upgrading to 24.04 it is still there

[Sabbir Hasan (sabbir4work)]

This problem is only with HDMI cables. I switched to Display port today and I no longer have that issue.

[Michał Fita (michal.fita)]

This is very interesting observation, maybe it'll help devs chase the bug.

Unfortunately for myself, I have only HDMI both in the notebook and the docking station.

[Crosshair (will-e-carlson)]

ubuntu 24.04 kernel 6.8.0-31-generic

lspci -k | grep -EA3 'VGA|3D|Display'
00:02.0 VGA compatible controller: Intel Corporation JasperLake [UHD Graphics] (rev 01)
 DeviceName: Onboard - Video
 Subsystem: Intel Corporation JasperLake [UHD Graphics]
 Kernel driver in use: i915

I've also installed mutter 46.1

Screen goes black/blank but does not turn off. This is very annoying since I have an oled monitor and this could cause burn in.

[Robin (digininja99)]

I've got the same thing on a fresh 24.04 install running X11. I've got three monitors, two on HDMI, one on display port.

I'm running the Nouveau drivers.

Locking with Super-L turns the backlight off for a few seconds then it comes back on, usually with the cursor showing as well.

I've just done some counting, 10 seconds after lock I get "no signal" on the screen, another 10 seconds and I get the login page, it then alternates between blanking and showing the login screen a few times before finally turning the display off but leaving the backlight on.

[Evan Andersen (evantandersen2)]

+1, fresh 24.04 install running wayland on intel drivers. At this point it seems like the bug affects many different setups.

xset dpms force off

Does trigger the correct behavior.

[Philipp Wendler (philw85)]

I can confirm #52: Works fine for me on DisplayPort, broken on HDMI.

My system is described in #21.

[fedsotto (fedsotto)]

+1, fresh 24.04 install running wayland on intel drivers.

[fedsotto (fedsotto)]

The MUTTER_DEBUG_ENABLE_ATOMIC_KMS didn't work for me neither

[Daniel van Vugt (vanvugt)]

MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0 is deprecated and replaced by:

  MUTTER_DEBUG_FORCE_KMS_MODE=simple

in Ubuntu 24.04.

[Daniel van Vugt (vanvugt)]

A black screen is not a security issue. We're only talking about backlight power here.

[CarpeDiemIsrael (carpediemisrael)]

Experiencing the same behavior as #55.
Locking with super+L urns off screen initially but after few seconds screen light goes back on.

[Sébastien Bouchard (sebastjava)]

I have the same bug as the OP. And the workaround number one also worked for me. However, I was reading all those comments and I found some little differences, listed below...

- on Ubuntu 24.04.1.
- on Wayland, and also tested on X11.

I get this bug on both Wayland and X11. Using either Super+L or the power saving settings.

I also logged on X11 and tested 'sleep 1; xset dpms force off'. Unlike the author and some other people here, this command didn't work either. The screen goes off and then back on a few seconds later.

#47 : BINGO ! "My bet is they send some message back to the computer when they change power state after requested to go to full power save. That in exchange wakes up the system, which then keeps the screen blank, but backlight don't go off (...)" — I think exactly the same. That's the only way I can explain this. Remember the workaround number one, in the OP: "Configure the monitor (in its own menus) to not auto-switch inputs." This is a clue.

#50 ♥ "We should solve this issue before Earth Day. It has caused a lot of wastage of electricity."

#60 : "MUTTER_DEBUG_FORCE_KMS_MODE=simple" in Ubuntu 24.04. I should try this.

This bug affects many people. I saw it on https://www.facebook.com/groups/ubuntudistros. And there are probably many duplicates. And thousands undetected and unreported.

@vanvugt Yes, this bug is not a security issue, but I would call it a "hardware durability" issue. When the LED backlight and the LCD stays on, it wears out faster. Over time, the color loses its accuracy. And then, eventually, the equipment breaks down and ends up in the trash.

[Daniel van Vugt (vanvugt)]

"some message back to the computer" is probably a hotplug (or unplug) event. That's why the first workaround works for you, because the monitor is no longer doing a logical disconnection when it goes to sleep.

If we could reproduce this reliably in development then it might be possible to just ignore events for a monitor reported as being unplugged while sleeping. Although you'd then have to deliver those events much later on wakeup so that in the case of a real unplug the desktop gets rearranged to match the new layout.

We could also just blindly ignore all unplug events if they're suspiciously close to when the monitor was put to sleep. But again, the bug needs to be reproducible in development.

Speculation like this is probably better discussed upstream (currently https://gitlab.gnome.org/GNOME/mutter/-/issues/1607) so that all GNOME developers can see it.

[Sébastien Bouchard (sebastjava)]

@vanvugt I tried adding
MUTTER_DEBUG_FORCE_KMS_MODE=simple
to /etc/environment and restart. It didn't work. On Ubuntu 24.04.1 LTS and Wayland.

[JackyMatt (imyhxy)]

@vanvugt How can I monitor those unplug events and try to debug this issue?

[Daniel van Vugt (vanvugt)]

I believe you can do it with "udevadm monitor".

[Sébastien Bouchard (sebastjava)]

@vanvugt "If we could reproduce this reliably in development (...)". I tested it many times here and it is absolutely constant, regular, persistent, stable.

- Monitor's internal settings > "Auto Input Switch" = on : This bug always shows, in every conditions.
- Monitor's internal settings > "Auto Input Switch" = off : This bug never shows, in every conditions.

"every conditions" means:
Ubuntu settings > screen power saving > screen blank -or- Ctrl+L -or- "sleep 1; xset DPMS force off"

And "screen blank" = "Turn the screen off after a period..." It is written right there, in those settings.

Here I have DisplayPort (DP) on my computer with an adapter to plug into an HDMI display.
on Ubuntu 24.04.1 on Wayland (except one test on X11)

[Philipp Wendler (philw85)]

Thanks for working on this!

The discussion about unplug events being the cause made me wonder whether this is also the source of a similar problem I have as well: On my ThinkPad T14 with Ubuntu 22.04 and Wayland, closing the lid wakes the notebook up from sleep mode. I.e., if I enter standby and then close the lid, the notebook wakes up. If I directly close the lid, the notebook enters standby mode and stays there. Of course it could also be that this is due to a different cause, but I wanted to mention it here in case it helps. I let "udevadm monitor" run through a "standby - close lid - wake up" cycle but the only "bind|unbind|add|remove" messages that it showed were for USB devices (plus some "change" messages for drm/card1 and my NVME disk).

For the problem with the HDMI monitor on my other machine I could produce an event log tomorrow if desired, or perform other debugging you would like to see. For me the problem also happens reliably on my other machine. (Though interestingly, on the monitor where my main machine shows the problem, my ThinkPad does not show it. Both run Ubuntu 22.04 Wayland and have an AMD GPU.)

[Michał Fita (michal.fita)]

OK, in my case my Lenovo L28u-30 doesn't have option to disable autoswitch.

What I noticed on 24.04, however, is that if I lock the screen with 🪟+L and the notebook (Lenovo P16s) screen goes full blank and then I turn off L28u-30 with switch, it stays blank (so I can save backlight).

But, if I leave the system to timeout to blanking, both screens seem to keep their backlight on.

P16s doesn't have DisplayPort, I could use one from docking station, but I have old one and the screen is 4K so I'm worried about performance over USB.

[JackyMatt (imyhxy)]

I login my system from SSH, and watch the udevadm monitor, those log is printing right before the screen wake up:

```plaintext
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[1095.780845] change /devices/pci0000:00/0000:00:02.0/drm/card1 (drm)
UDEV [1095.808801] change /devices/pci0000:00/0000:00:02.0/drm/card1 (drm)
KERNEL[1096.322808] change /devices/pci0000:00/0000:00:02.0/drm/card1 (drm)
UDEV [1096.329510] change /devices/pci0000:00/0000:00:02.0/drm/card1 (drm)
```

By the way, I don't have a discrete graphics card.

[Sébastien Bouchard (sebastjava)]

I log into a "classic" x11 session and do this:

sleep 1; xset dpms force off; sleep 15; xset q | grep "Monitor is"

And then I read "Monitor is Off", which is clearly displayed, visible, on this monitor which is supposedly "Off"...

[Gari (ggonz)]

Same issue, using Asus NUC
24.04.1

[Maicon (maicon-ba)]

Change from HDMI to DisplayPort cable works for me.

Ubuntu 24.10
Monitor Philips 276E
Radeon 740M Graphics

[Michał Fita (michal.fita)]

This bug is supposed to be fixed in the kernel driver:
https://bugzilla.kernel.org/show_bug.cgi?id=215203

Then it's been reported this workaround help people who don't have other option (like me) than HDMI and their monitor doesn't have menu option to disable automatic switching between ports:
https://gitlab.freedesktop.org/drm/amd/-/issues/1840

I can't confirm yet if that workaround works for me.

[Sébastien Bouchard (sebastjava)]

Same issue here.
CPU: Intel Core i5-6500
Graphics: Intel HD Graphics 530 (integrated GPU)
Monitor: LG 24MR400-B (HDMI)

Computer with DisplayPort connected to HDMI monitor with an adapter.

[Sébastien Bouchard (sebastjava)]

@jmairey Sorry, but I disagree.

Well, first of all, I have to agree with you on one thing: these settings are confusing, yes. But I doubt you found the solution to the problem.

REMINDER: When you do tests, don't forget to "undo" your workaround, obviously!

1. Blank Screen delay can be adjusted from 2 places:
    - Settings > Power settings
    - Settings > Privacy & Security > Screen Lock

That's just redundancy for the SAME setting... Try changing it from one place and you will find an echo in the other place... I agree this can be confusing...

2. Check your own first screenshot, i.e. Power Saving:
    "Screen Blank = Turn the screen off..." It is written right there!

TO REPRODUCE: (see screenshot)

1. Settings > Privacy & Security > Screen Lock:
    - Blank Screen Delay: 1 minute
    - Automatic Screen Lock: on
    - Automatic Screen Lock Delay: Screen Turns Off
2. Wait > 1 minute
3. See? Screen is blank but not off. (Turn off the surrounding lights and look closer...)

According to you, these steps to reproduce should solve my problem and turn the screen off. But it doesn't work. Not here, at least. The screen is blank, and locked, but not off.

And the shortcut for screen lock (🪟+L) gives the same results: locked, blank, but not off.

Please correct me. Tell me exactly what I have to do to, step-by-step, to make it work.

Otherwise, let's say it again and for the hundredth time: the only thing that works is the OP's workaround #1: Configure the monitor (in its own menus) to not auto-switch inputs. And that's not normal. It looks like some sort of "feedback loop" between the monitor and the computer...

[John Milligan Airey (jmairey)]

@sebastien. yes, you are right. after a few seconds of no back light, the back light returns.

furthermore, for me, configuring the monitors (in their own menus) to not auto switch input does fix anything.

so I am turning off the monitors manually.

[John Milligan Airey (jmairey)]

The work around of setting my monitors to not auto select does appear to work for me.

But also... For one of my two new 24.04 machines, the connection is from hdmi out through a dvi adaptor to an older monitor. that machine has no problem with fully blanking the monitor. maybe it is some sort of hdmi audio handshake that results in waking up the new IPS monitors and ends with them having their backlights lit?

The only display port connections I have are USB-C, so I would need a usb-c to full size display port adapter or cable, which I do not have on hand.

But I will try this below, with the monitor autoselect turned back on:
https://askubuntu.com/questions/1165209/disable-hdmi-audio-on-ubuntu-studio-19-04
because dvi has no audio, unlike hdmi.
I use an outboard USB DAC and headphone amplifier on both my machines, not the HDMI audio.
This did not fix the monitor blanking. the only workaround seems to be turning off autoselect input using the monitors own menu.

[Schlomo Schapiro (sschapiro)]

While it is nice to have a workaround based on changing the configuration in the screen, I'd really appreciate to get an actual fix.

I actually need my screen to stay with "auto select input" ON because I have a screen with built-in KVM switch and use 2 devices (PC & laptop). Therefore disabling this option is not possible for me.

Any ideas on an actual fix? With Ubuntu 22.04 on the same hardware I had no problems at all.

[Michał Fita (michal.fita)]

Oh man, we all'd be glad if this is fixed finally. But this bug has been reported 1.5y ago, others and upstream even earlier. In theory there were fix in upstream Gnome, but then they broke it again. It doesn't seem likely Canonical would ever backport them before actual pick of new Gnome takes place - no one seem to care we burn our screens and waste energy. We probably have to wait another 2 years to any fixes to materialize I'm afraid.

[Gari (ggonz)]

Same issue. I can't make that change on the screen I have (ThinKVision)