lxqt-config-monitor forces logout with multiple monitors when using nouveau

[Zebediah Boss]

using from the menu > Preferences > lxqt settings > monitor settings

you will be logged out when trying to apply any changes you make to the monitors. ie moving one from left to right

However using xrandr to achieve the same and it just works

Install nvidia drivers and use the nvidia-settings to do the same thing - just works (as does lxqt-config-monitor)

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP104 [GeForce GTX 1070 Ti] [10de:1b82] (rev a1)
 Subsystem: ZOTAC International (MCO) Ltd. GP104 [GeForce GTX 1070 Ti] [19da:2445]
 Kernel driver in use: nouveau
 Kernel modules: nvidiafb, nouveau

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: lxqt-config 0.13.0-0ubuntu3
ProcVersionSignature: Ubuntu 4.17.0-9.10-generic 4.17.17
Uname: Linux 4.17.0-9-generic x86_64
ApportVersion: 2.20.10-0ubuntu9
Architecture: amd64
CurrentDesktop: LXQt
Date: Mon Sep 3 21:49:32 2018
InstallationDate: Installed on 2018-09-03 (0 days ago)
InstallationMedia: Lubuntu 18.10 "Cosmic Cuttlefish" - Alpha amd64 (20180901)
SourcePackage: lxqt-config
UpgradeStatus: No upgrade log present (probably fresh install)

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

I helped troubleshoot this with him on IRC. Looking at their dmesg and syslog, it looks like nouveau is failing in some way, which is causing kscreen to fail in some way. Weird that it works with xrandr.

[Zebediah Boss (zebedee-boss)]

Just as a side note - you also get booted back to a login screen when trying to scale with xrandr

ie 'xrandr --output DP-2 --scale 0.8x0.8' or 1.5x1.5

[Alf Gaida (agaida)]

> scake with: xrandr --output DP-2 --scale 0.8x0.8' or 1.5x1.5

differnt bug, not LXQt-related.

I guess using xrandr is related to HiDPI - i would suggest to solve that with an .Xresources file containing `Xft.dpi: $your_dpi_in_integer` - the maybe better idea is not to use nouveau first hand.

[Chris Guiver (guiverc)]

Thank you for reporting this bug to Ubuntu.

Ubuntu 18.10 (cosmic) reached end-of-life on July 18, 2019.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in.

[Launchpad Janitor (janitor)]

[Expired for lxqt-config (Ubuntu) because there has been no activity for 60 days.]