A resolução máxima que xrandr
mostra é a do tamanho máximo da tela virtual.
A informação mais próxima que posso encontrar para ajudá-lo com sua pergunta é:
link
Snipet:
Let’s have a look at the maximal virtual screen size, we see 4096x4096 in this example:
$ xrandr|head -1
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 4096 x 4096
With DRI and without KMS, that might be needed. Indeed, drivers will often create a default virtual screen with small dimensions, for instance 1600x1200, to reduce memory consumption.
If you plan to use multiple outputs displaying different zones, you should configure your xorg.conf by adding a Virtual line to the Display subsection in the Screen section.
Section "Screen"
…
SubSection "Display"
Depth 24
Virtual 3000 2000
EndSubSection
EndSection
Veja também o link
Espero que isso ajude!