Thierry de Coulon wrote:

> My problem is this: while I have the screen resolution setup to 1920x1080
> (and trinity desktop looks OK for this resolution), the monitor (which is
> accessed from HDMI through an HDMI to VGA converter because I use a KVM
> that needs VGA connectors) was initially "seen" as 1024x768.

It is interesting to know what is the output of xrandr

I have/had similar issues with my notebook(s) and external monitor. Natively
eDP1 supports  1366x768, while monitor does 1920x1080.

So switching on and of the one and the other messed up from time to time the
modesettings and I end up with unusable resolution. The external would
refuse to accept 1920x1080. It improved recently with later 4.9 kernel and
I did not test extensively.
One option was to configure monitors in xorg.conf with their mod lines. I
did this on the older notebook
I however use now xrandr --scale as X tends to pick up the lowest common and
it can not support different resolutions or whatever. So I put the bigger
one to  1920x1080 and scale eDP1., which gives acceptable output.

I have read of similar issues with KVM.

regards