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: 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. But I am not going to reboot this machine immediately to test it out. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-settings-daemon in Ubuntu. https://bugs.launchpad.net/bugs/1971434 Title: Display powersave only blanks, but does not turn off Status in Mutter: New Status in gnome-settings-daemon package in Ubuntu: Triaged Status in mutter package in Ubuntu: Triaged Bug description: [ 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 ] To manage notifications about this bug go to: https://bugs.launchpad.net/mutter/+bug/1971434/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
