On Fri, 18 Oct 2024 at 13:28:05 +0100, Stuart Henderson wrote: > I've not got a test machine running yet, but from observations (I > haven't gone through all the logs to verify, those "seconds after start" > logs are a pain to correlate with time of day!) it seems to only happen > when the monitor is in a dpms power-saving mode. Not sure if that > rings any bells..
As I mentioned earlier, running xrandr or xbacklight makes it print the modelines in Xorg.0.log and if your monitor has a lot of them, it will print a ton. nano:~$ wc -l /var/log/Xorg.0.log 809 /var/log/Xorg.0.log nano:~$ xbacklight -set 80 nano:~$ wc -l /var/log/Xorg.0.log 905 /var/log/Xorg.0.log nano:~$ xbacklight -set 20 nano:~$ wc -l /var/log/Xorg.0.log 1021 /var/log/Xorg.0.log When the monitor is off, is a screensaver running? Maybe it's constantly checking xrandr to find new monitors attached? Or some other thing in mate that is adjusting backlight?