Screen blanking but not turning off on Raspberry pi 4 running Ubuntu 22.04.1 image

user697440

11/14/23, 4:59 PM

I am using a Raspberry Pi 4B and an HDMI monitor (since tested on both an old 4GB model from launch and my newer 8GB model). The pi is running the Ubuntu 22.04.1 Raspberry Pi desktop image from the Ubuntu website (freshly downloaded and reinstalled yesterday, just to make sure).

Last I checked (admittedly sometime before April 2022, when I moved to Ubuntu), a RaspiOS image* would turn off the screen backlight when the screen is blanked, but this Ubuntu image will turn the screen pixels black but the backlight remains on. (Actually, the screen does briefly go into power-save mode, but then it turns back on to show the black screen. This still happens even with no devices connected to the Pi.)

The screen will turn off if my desktop PC blanks the screen when I have it connected, and the screen backlight also turns off if I shut down the Pi (even if power to the pi remains on afterward).

This used to be a reported bug with the raspberry pi 4 (circa 2019-2020), but I was under the impression that it was since solved, as it works on RaspiOS* and the GitHub issue was closed.

I have tried adding "hdmi_blanking=1" to /boot/firmware/config.txt, but that didn't help even after a reboot. Adding the gpio-fan commands to that file does provide fan control, so this seems to be the correct config.txt even if it's been moved in the Ubuntu image.

*RaspiOS - the official Raspberry Pi Foundation image.

Update: I discovered that, as of April 2nd, the problem was resolved. I couldn't find any reference to it in the Ubuntu bug tracker using the normal keywords (such as "screen," "monitor," "blanking," "fails to turn off" or any synonym thereof), but there does seem to have been another bug report from the Raspberry Pi side of things.

It appears to have been something with xserver-xorg-core, and has apparently been fixed since mid-March.

918

0 + 4

power-management

hdmi

screen

raspberrypi

Sgdva

11/18/23, 4:26 AM

I'm in the same problem, I have tried creating a [service](https://askubuntu.com/questions/1244358/ubuntu-20-04-server-turn-off-screen-until-i-press-a-key), I never found a [grub](https://askubuntu.com/questions/1351533/how-to-turn-off-monitor-on-ubuntu-server), then [vbetool](https://askubuntu.com/questions/7295/how-to-turn-off-the-display-via-the-command-line) won't install and the ssh commands [xset](https://askubuntu.com/questions/62858/turn-off-monitor-using-command-line) fail as well

Sgdva

11/24/23, 5:10 AM

I set up a bounty because it's something that it's bugging me too, I just installed the display and it's annoying to have it on when should be off and on only on demand by ssh commands. I hope that this draws more attention and if anyone has found a solution or workaround would be awesome

Elon Musk

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