I would suggest a workaroung: use --scale together with --panning
For example, if I have 1366x768 screen and I would like to scale it up to 1920x1080, I would use
xrandr --output LVDS1 --panning 1920x1080 --scale 1.406x1.406
1.406 = 1920/1366 or, similarly 1080/768
To go back, issue
xrandr --output LVDS1 --panning 0x0+0+0 --scale 1x1
Of course, don't foget to replace LDVS1 with the appropriate device.
I would suggest a workaroung: use --scale together with --panning
For example, if I have 1366x768 screen and I would like to scale it up to 1920x1080, I would use
xrandr --output LVDS1 --panning 1920x1080 --scale 1.406x1.406
1.406 = 1920/1366 or, similarly 1080/768
To go back, issue
xrandr --output LVDS1 --panning 0x0+0+0 --scale 1x1
Of course, don't foget to replace LDVS1 with the appropriate device.