I am trying to to add a resolution mode for X with the xorg-dummy driver to be able to fit the x11vnc server's output to my screen resolution. I am running
x11vnc -xdummy -xrandr
with the x11vnc Xdummy script in my path. If I don't add a xorg.conf file in /etc/X11 then I get only a bunch of lower resolutions.
Therefore I added this xorg.conf file https://www.xpra.org/xorg.conf with which I also have a number of higher resolutions. Among them is 1920x1200 which I need, but rotated by 90 degrees.
Using http://www.arachnoid.com/modelines/ , I therefore computed the Modeline
Modeline "1200x1920_10.00" 27.20 1200 1192 1304 1408 1920 1921 1924 1932 -HSync +Vsync
And added it to the xorg.conf file together with the corresponding Mode. After restarting, however, I still don't have this mode. In my /var/log/Xorg.log I see thigs like
Not using mode "1200x1920" (no mode of this name)
Not using mode "1920x1200" (no mode of this name)
The later works in fact. The former does not. I also tried adding it with xrandr, but I get
Failed to get size of gamma for output default
Furthermore I tried supplying the mode using the argument -geom 1200x1920 to the Xdummy script. This does not add the resolution either.
Does xorg-dummy only support the modes already specified in the sample xorg.conf or am I making a mistake? The goal of of the exercise is to be able to switch the vnc-server resolution dynamically. I could use other vnc-servers but most of these seem to have issues related to the use of KDE. KDE's own krfb is unfortunately much slower.