Setup: Ubuntu, Openbox, notebook, occasionally an external screen.
I’ve set things up so that if an external monitor is attached when I start my notebook, a script (run by Openbox’s autostart), xrandr makes that the primary monitor.
What I’d like to do is run that script when I turn off or otherwise disconnect that external monitor, so that I can make the notebook’s built-in screen the primary again. Does anyone here have any ideas how to do that automatically?
there’s a file called
status
incat /sys/class/drm/card0-CONNECTION
whereCONNECTION
is the namexrandr --listmonitors
shows on the right. So e.g. for me it looks like this:$ xrandr --listmonitors Monitors: 2 0: +*DP-3 2560/553x1440/311+0+430 DP-3 1: +DP-5 1440/553x2560/311+2560+0 DP-5 $ cat /sys/class/drm/card0-DP-3/status connected
You can watch this file with
inotifywatch -e modify
. You can put this in a systemd.path unit which calls your script as a one-shot or with an environment parameter.You can also use srandrd but IMHO that’s a bit overkill when you can do it with pid0 tools 😅
Hmm. Maybe I’m doing something wrong but doing
only gives me “No events occurred.” (after ctrl-c stops it). Oddly, I can see the file contents change (connected to disconnected and back again) if I cat it in a separate term window so I don’t know what’s going on.
hm, maybe you need another event type. What GPU is it?
Events: access file or directory contents were read modify file or directory contents were written attrib file or directory attributes changed close_write file or directory closed, after being opened in writeable mode close_nowrite file or directory closed, after being opened in read-only mode close file or directory closed, regardless of read/write mode open file or directory opened moved_to file or directory moved to watched directory moved_from file or directory moved from watched directory move file or directory moved to or from watched directory move_self A watched file or directory was moved. create file or directory created within watched directory delete file or directory deleted within watched directory delete_self file or directory was deleted unmount file system containing file or directory unmounted
May be
create
ordelete
oh dear. I just found autorandr which might be what you’re looking for and probably a fair bit easier than what I suggested initially.