I need to show some movies on different monitors using a video card with 8 HDMI ports on a workstation, and I need to have all done automatically everytime the workstation starts, without use intervention. I had no time yet to practice with this card, but I also have a card with two HDMI and a VGA ports on my PC at work, so I made some experiments.
I'm using GNOME on Debian Stretch, and GNOME allows me only to arrange the two monitors as a unique virtual bigger screen (besides other configurations such as mirroring I'm not interested in). If I have to show a window on a specific monitor I can only use some sort of xdotool/wmctrl command.
Also, I see some confusion between displays and workspace. I can move or show a new window on a specific workspace, but that's useless for me.
I got some decent results using xrandr to put the two monitors side by side (they have different resolution, but this is not a problem for me) and then using xdotool to move a window to the right far enough to have it on the second monitor. But this is rather complicated.
My first thought was using the DISPLAY variable this way:
$ DISPLAY=:0.0 xterm
$ DISPLAY=:0.1 gedit
The first command works, but the second says "cannot open display :0.1".
I'm sure there must be an easier solution.
Thanks in advance.