Fedora 25, Wayland, and HiDPI display

fedorawayland

I just upgraded my ThinkPad T560 from Fedora 24 to Fedora 25.

On Fedora 24, I used these commands:

$ xrandr --output eDP-1 --scale 1.25x1.25
$ xrandr --output eDP-1 --panning 3600x2025

to set up proper scaling. These commands no longer work on Fedora 25:

$ xrandr --output eDP-1 --scale 1.25x1.25
warning: output eDP-1 not found; ignoring

Apparently the display identifier is now XWAYLAND0 (and not eDP-1 anymore):

$ xrandr -q
Screen 0: minimum 320 x 200, current 2880 x 1620, maximum 8192 x 8192
XWAYLAND0 connected 2880x1620+0+0 340mm x 190mm
   2880x1620     59.92*+

However, using this new identifier with the old command also does not work:

$ xrandr --output XWAYLAND0 --scale 1.25x1.25
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  139 (RANDR)
  Minor opcode of failed request:  26 (RRSetCrtcTransform)
  Value in failed request:  0x20
  Serial number of failed request:  22
  Current serial number in output stream:  23

As a short term solution I choose "GNOME on Xorg" on login. Then I can use the xrandr commands shown above as before.

Can somebody please point me to a how-to for properly setting up HiDPI displays on Fedora 25?

Best Answer

GNOME Shell on Wayland — which is what Fedora 25 Workstation uses — does not support non-integer scaling factors. There's some preliminary work but nothing decided yet; right now, the workaround you already chose (fall back to X11) is the right one.

Alternately, you can choose an integer scaling factor and then use tweak-tool to change font sizes to make things more readable. That doesn't scale non-text elements, of course, but it gives a little more flexibility (and readability).

Related Question