xrandr scaling, and mouse issue

Question

I see others have come across this issue, but I can't seem to find a solution. I'm running Ubuntu 16.10 on a Dell Precision 5510. My laptop screen is 4K, and an external monitor is 2560x1440. I'm trying the following:

xrandr --output HDMI-1 --scale 1.7x1.7 --auto --output eDP-1 --scale 0.7x0.7 --left-of HDMI-1

(eDP-1 is the laptop monitor).

This adjusts the resolutions beautifully, but there's this block of area on the right (HDMI-1) monitor that my mouse can't go on. I tried adding --panning 4352x2448 (that's the HDMI's resolution x 1.7), and it kind of works, but then when moving the mouse, it kind of pans the laptop's contents on the HDMI screen. I somehow got this working on Friday, but installed some Ubuntu updates, and can't get it to work as expected any more. Is there a simple trick to enable me to use the mouse on the scaled display?

I'm running xrandr 1.5, if that's useful.

Solution 1

It seems that

xrandr --output HDMI-1 --scale 1.7x1.7 --auto --panning 4352x2448+3840+0 --right-of eDP-1
xrandr --output eDP-1 --auto --scale 0.7x0.7

seems to work fine.

Solution 2

Just do this:

For ordinary laptop with:

• primary ID : LVDS1
• Resolution : 1366x768

and want to upscale resolution to 2049x1152 with no invisible border mouse, put this on your terminal:

xrandr --output LVDS1 --mode 1366x768 --rate 60 --fb 2049x1152 --panning 2049x1152 --scale-from 2049x1152

That goes for HDMI, etc. It works everywhere.

Comments

[Afshin Mehrabani]

Yup, that's correct. the problem can be solved by adding that panning parameter.