Hi all,
I've recently acquired a new Dell desktop, featuring a display card with both VGA and HDMI output. The monitor can also take both as input. As HDMI has better quality I naturally want to get the output there.
The problem is, X consider the two as separated displays, and gdm3 would always output the login screen to both inputs, where VGA is the primary, HDMI is the secondary, in extended mode. This means I can only login if I can see the VGA output. After login I can change the display settings to mirror, so that I can see the output in HDMI. But that doesn't change the login screen.
I've searched the web for a while, and there are essentially two solutions. One is to put an xrandr command in /etc/gdm3/Init/Default. I've experiment it for a while, until I conclude that in my Debian stretch installation, the file is not run at all: putting something like "echo hello > /tmp/hello" into that file will not create the /tmp/hello file after X gets started.
The other solution is to copy my ~/.config/monitors.xml to ~Debian-gdm/monitors.xml. Again, nothing happen, the file simply gets ignored.
I've also tried to add something to /etc/init.d/gdm3, thinking about whether I can run xrandr after I detected gdm is running. But I noticed that it won't work, as Debian is now using systemd, and the later part of the script won't run.
Anything I've missed?
Regards,