Incorrect desktop panning since fractional scaling was implemented for x11. (All distros)
Affected version
Seems to happen on all Distros using gnome on x11. Tested in: Fedora 39, Ubuntu 23.10, Vanilla OS 22.10 Kinetic. All of the versions affected by this problem include "Fractional scaling" as a new option in the displays app.
Bug summary
The new method of fractional scaling will scale the smaller monitor to be equal to the bigger one, causing problems with application scaling. Instead of this, I always set my 4k monitor to work as a 1080p monitor in this way:
This always worked perfectly, but now, even with fractional scaling disabled, the resulting screen is not 3840x1080 as it should, but 5760 x 2160 as shown by xrandr. This causes you to pan the view out of the 1080p desktop, going out of bounds (It can be seen better opening the image in another tab, as the part out of the desktop is shown as white/transparent on the screenshot):
Note that this only happens if scale the 4k monitor to be of a smaller resolution and use viewportout to be 3840x216, making them align.
Steps to reproduce
- Open displays.
- Disable fractional scaling.
- Open nvidia settings and scale the 4k monitor to be 1080 but out to 4k to fill the monitor.
- You can now pan outside the desktop. and the xscreen size is wrong.
What happened
Mutter ignores the correct setup, the xcreen size do not match, and i can pan outside the desktop.
What did you expect to happen
As always, I expected to have a simple 1080 dual setup, without panning outside the desktop.