There's no need for a vv6 "completely disabling fractional scaling" because that's the first thing we already tried in vv1 and it didn't work as mentioned in comment #11. If you want to test it again then see https://launchpad.net/~vanvugt/+archive/ubuntu/mutter/+build/26236293
> I did test that with a Cinnamon session and confirmed it. I basically did: > xrandr --output VNC-output-1 --auto > and it immediately goes to a blank screen Cinnamon might not be the best test case because it used to be based on mutter. We need to test a desktop environment that has no relation to mutter to confirm that's a bug in the DCV viewer/server. Or any simple X session with a legacy window manager? > - Fractional scaling is supported in RandR 1.3 or newer > - Xdcv reports its RandR version is 1.6, but when you try to use fraction > scaling it errors (error id 2) I want to say that's an Xdcv bug but by chance I am working on NVIDIA right now and find it returns the same errors from xrandr --scale or --transform. Yet somehow fractional scaling still works on NVIDIA!? This might not matter because so far this issue has not stopped us from progressing on the main revert bug 2020782. > - The corruption bug 1924689 may be caused by the fractional scaling patch (or a side effect of the "error id 2"?) Maybe, not sure. It won't take much effort to confirm if the same mutter corruption bug occurs without the fractional scaling patch. But it's also a separate bug so I would prefer to keep that conversation separate. > - Xdcv is reporting a bogus refresh rate That's an Xdcv bug which is probably also intentionally a design feature. I think it should be fixed in Xdcv because this design will break other compositors like it has broken mutter. Technically correct compositor behaviour would be to render at 0Hz, which would not be usable ;) So Xdcv probably should be changed to avoid the same problem occuring in other desktop environments. > - There's a "config history" issue identified by Mustafa in comments #26 and #30 The config history raised by Mustafa in comment #30 should be treated as an enhancement request and logged elsewhere to avoid confusing this bug. That enhancement only makes sense to virtual machines running Xorg sessions. I want to keep this bug focussed on the failure to revert because the conversation gets too complex otherwise. And also to avoid the expectation that multiple bugs should be fixed under a single bug number. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2020782 Title: Xdcv: Changing display scale setting and reverting it fails Status in mutter package in Ubuntu: In Progress Bug description: In Amazon Workspaces running Ubuntu 22.04, when attempting to change the Scale in the Gnome Display settings, if you click on a different scale (i.e. changing from 100% to 200%) and hitting apply, it will bring up a prompt asking if you want to keep or revert the changes and there will be a timer of 20 seconds. If you try to revert the changes (either by letting the timer expire or by clicking the "revert" button), we will hit one of the following two behaviors: 1 - The setting won't revert and will keep scaled 2 - gnome-shell will show some error messages in syslog and the display will be "corrupted", where the only window you are able to click is the display setting and if you try to drag it, it will leave a "blur" throughout the window (per discussions, this seems to be https://launchpad.net/bugs/1924689) For both situations, changing the display resolution (i.e. going into and out of full screen in the workspaces client) will fix the issue When hitting situation 1, syslog shows: May 17 17:33:10 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to restore previous configuration: Invalid mode 1920x1080 (19.958942) for monitor 'unknown unknown' When hitting situation 2, syslog shows: May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to restore previous configuration: Invalid mode 1920x984 (19.895834) for monitor 'unknown unknown' May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use stored monitor configuration: Invalid mode 1920x984 (19.895834) for monitor 'unknown unknown' May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use linear monitor configuration: Invalid mode 800x600 (-nan) for monitor 'unknown unknown' May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use fallback monitor configuration: Invalid mode 800x600 (-nan) for monitor 'unknown unknown' May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Impossible to set scaling on crtc 59 to 1.000000, error id 2 May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Xlib: extension "DPMS" missing on display ":1". May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: Object St.Label (0x557090d07de0), has been already disposed — impossible to access it. This might be caused by the object having been destroyed from C code using something such as destroy(), dispose(), or remove() vfuncs. May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: == Stack trace for context 0x557090bee180 == May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: #0 557093f00e68 i /usr/share/gnome-shell/extensions/ubuntu-d...@ubuntu.com/appIcons.js:1349 (2cdac32b2e20 @ 105) May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: #1 557093f00dd8 i /usr/share/gnome-shell/extensions/ubuntu-d...@ubuntu.com/dash.js:42 (2cdac32a5d80 @ 27) May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: #2 557093f00d58 i resource:///org/gnome/shell/ui/dash.js:545 (20c3e0d20970 @ 24) May 17 17:31:24 U-1AZMIM8SIPZ6I gnome-shell[3030]: JS ERROR: TypeError: monitor is null#012_updateWorkAreaBox@resource:///org/gnome/shell/ui/overviewControls.js:58:26#012_init/<@resource:///org/gnome/shell/ui/overviewControls.js:51:45 Sometimes the stack trace isn't shown, but the symptom is the same: May 17 18:31:39 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to restore previous configuration: Invalid mode 1920x984 (19.895834) for monitor 'unknown unknown' May 17 18:31:39 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use stored monitor configuration: Invalid mode 1920x984 (19.895834) for monitor 'unknown unknown' May 17 18:31:39 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use linear monitor configuration: Invalid mode 800x600 (-nan) for monitor 'unknown unknown' May 17 18:31:39 U-1AZMIM8SIPZ6I gnome-shell[3030]: Failed to use fallback monitor configuration: Invalid mode 800x600 (-nan) for monitor 'unknown unknown' May 17 18:31:39 U-1AZMIM8SIPZ6I gnome-shell[3030]: Impossible to set scaling on crtc 59 to 1.000000, error id 2 May 17 18:31:40 U-1AZMIM8SIPZ6I gnome-shell[3030]: Xlib: extension "DPMS" missing on display ":1". I'm unable to reproduce the problem if I manually install ubuntu-desktop and use the Nice DCV Server (as used by Workspaces) by following the steps from (using the xorg-x11-drv-dummy): https://docs.aws.amazon.com/dcv/latest/adminguide/setting-up- installing-linux.html One relevant difference is that Workspaces uses a custom X11 server /usr/bin/Xdcv, instead of /usr/lib/xorg/Xorg, and they have the following process being started: /usr/bin/Xdcv -output 800x600+0+0 -output 800x600+800+0 -output 800x600+1600+0 -output 800x600+2400+0 -enabledoutputs 1 vt2 -displayfd 3 -auth /run/user/541001128/gdm/Xauthority -nolisten tcp -background none -noreset -keeptty -novtswitch -verbose 3 I'm also unable to reproduce the problem using xrdp + Xorg. While discussing this with the desktop crew, it was mentioned that we see the same problems in Xorg. And to a much lesser extent some issues in Wayland too when changing scales. mutter and gnome-shell versions being used: $ sudo apt-cache policy mutter-common mutter-common: Installed: 42.2-0ubuntu1 Candidate: 42.5-0ubuntu1 Version table: 42.5-0ubuntu1 500 500 http://sa-east-1.ec2.archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages *** 42.2-0ubuntu1 100 100 /var/lib/dpkg/status 42.0-3ubuntu2 500 500 http://sa-east-1.ec2.archive.ubuntu.com/ubuntu jammy/main amd64 Packages $ sudo apt-cache policy gnome-shell gnome-shell: Installed: 42.4-0ubuntu0.22.04.1 Candidate: 42.5-0ubuntu1 Version table: 42.5-0ubuntu1 500 500 http://sa-east-1.ec2.archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages *** 42.4-0ubuntu0.22.04.1 100 100 /var/lib/dpkg/status 42.0-2ubuntu1 500 500 http://sa-east-1.ec2.archive.ubuntu.com/ubuntu jammy/main amd64 Packages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2020782/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
