Fractional Scaling resets after reboot

[Oscar Parada]

During the 20.04 development fractional scaling will not stick after a reboot, and display arrangement reset as well. Bug persisted in the Beta, and now in the final release. I know fractional scaling is "experimental" but i would think that it would persist after reboots.

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:

  apport-collect 1874559

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Sebastien Bacher (seb128)]

Could you also give details on the session you are using (xorg or wayland), the video driver and the screens?

[Simone Liguori (simone-liguori)]

I'm copying my comment from bug 1857383 as I think this one is more pertinent. I'm on xorg, you can find the apport information in bug 1857383 starting comment #22.

Using the NVIDIA driver I was affected by bug 1870736 and bug 1873403.
I moved to the Nouveau drivers and the issues above were gone.

However, I notice a strange issue with display settings persistence.

I have 2 screens (HDMI3-3 FHD, DP-1 4K primary), which I'd like to have respectively at 100% and 150% scale:
$ xrandr | grep " connected"
DP-1 connected primary 5120x2880+3840+0 (normal left inverted right x axis y axis) 607mm x 345mm
HDMI-3 connected 3840x2160+0+302 (normal left inverted right x axis y axis) 160mm x 90mm

Whenever I set the 4K screen to 150% scale, any changes won't persist after reboot. If I change any other settings (like changing screen positions), leave scale as 100%, the changes I make do persist on reboot.

If after reboot I attempt to set 4K screen to 150% not only the change won't persist after reboot, but it will go back to the initial state (effectively undoing the previous changes too).

How do I reproduce the issue:

1) Ensure my system is on Nouveau drivers
2) HDMI-3 (FHD) is currently on the right, DP-1 (4K) on the left
3) Display settings, swap screen positions: HDMI-3 (FHD) on the left, DP-1 (4K) on the right
4) Reboot
5) Verify changes persisted: HDMI-3 (FHD) is on the left, DP-1 (4K) on the right
6) Set DP-1 scale to 150%
7) Reboot
8) Verify not only changes didn't persist, but the status is back as 2), with screens going back to their original position

[Oscar Parada (oparada1988)]

Im using a Radeon 5700XT, with xorg. Pretty much same issue as Simone Liguori. Im not using the pro driver, and on wayland when enabling fractional scaling it wont show the options, even after restarting gnome sell.

[Daniel van Vugt (vanvugt)]

I've just generalized bug 1825593 so we should use that.