I want to get run a comand if I am plugging or unplugging VGA cable.
SUBSYSTEM=="drm",ACTION=="add",RUN+="/usr/bin/touch /home/manuel/UDEV______A" SUBSYSTEM=="drm",ACTION=="remove",RUN+="/usr/bin/touch /home/manuel/UDEV______R" SUBSYSTEM=="drm",ACTION=="change",RUN+="/usr/bin/touch /home/manuel/UDEV______C"
UDEV______C is created, but why not UDEV______A, UDEV______R?
It's _not_ impolite, please feel free to correct my english.
There is no add and remove concerning external screens/concerning the drm-subsystem. At least udev doesn't throw them, which is the same in this case. There's just change.
Also detecting monitors over vga is _really_ unreliable anyway, so even if there was it might not work to your satisfaction.
This seems to be very true, unfortunately. I have a screenupdater relying on that and it could definitely do better.