Matebook and Presentation Woes in Ubuntu

I am very happy with my matebook, and the screen resolution is a big part of it. One problem that became glaringly obvious recently was that in Ubuntu, I could not mirror displays. So here I am plugging my beautiful laptop to whatever third rate projector is lying about and I am stuck with extended displays.

Maybe this would not be so bad if I did not need to do some demonstrations in class. It is important that I can see what students are seeing without bending into weird shapes. So I dug in and noticed that Ubuntu only recognizes one resolution for the glorious display on the matebook. 3000×2000@60Hz and nothing else.

When you try to mirror to a projector with 1024×768@30Hz, the lack of a common resolution prevents mirrored screens.

I had to use cvt to calculate vesa mode lines.

cvt 1920 1080

Then I used xrandr to define a new mode based on cvt output

xrandr --newmode "1920x1080_59.96" 173 1920 2048 2248 2576 1080 1083 188 1120 -hsync +vsync

Finally I added the new mode to built in display

xrandr --addmode VGA-1 1920x1080_59.96

Next time you plug external display in, you can use mirror displays (as long as there is a common resolution for both displays). Not too much effort and it works.