> Try logging into a non-GNOME Xorg session on Workspaces > if you can. Then use the 'xrandr' command to set a mode > to turn on one of the unused virtual monitors. If that > causes the DCV client to go blank then we have proven > it's not mutter's fault.
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 OK, so saying out loud my understanding of this issue so far, so as to check it's correct. The problems are: - 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) - The corruption bug 1924689 may be caused by the fractional scaling patch (or a side effect of the "error id 2"?) - Xdcv is reporting a bogus refresh rate - There's a "config history" issue identified by Mustafa in comments #26 and #30 What we've been doing now to try to narrow it down is: A - The "Zero Hz" fix is basically loosening mutter to accept zero-Hz, as this is the bogus refresh rate being reported by Xdcv B - vv4 fix = no fractional scaling + "zero Hz" fix C - vv5 fix = re-adds fractional scaling + "zero Hz" fix And out of it, we've confirmed in local VM / Workspaces tests that 1 - Without fractional scaling patch (vv4) / with fractional scaling disabled, we can't reproduce the "Failed to restore previous configuration: Invalid mode" / "Impossible to set scaling on crtc" errors 2 - The "Zero Hz" fix causes a side-effect of enabling the unused monitors (tbd if this is a bug) 2a. If you manually disable 3 monitors (keeping only one) and then try to apply / revert 200% scale, it errors [1] and sets resolution back to 800x600 3 - When enabling unused monitors in Workspaces, we get a blank screen (which I've confirmed through cinnamon / xrandr that it must be a problem with the Workspaces client when enabling a monitor) For the "zero Hz" problem, if I understand correctly, it is a bogus issue without a noticeable impact in usage. On the other hand, due to the "zero Hz" fix introducing problems 2 and 2a above, I'm skeptical on validating that avoiding fractional scaling fixes our issue (item 1 above). If the "zero hz" issue is really just bogus, should we try a "vv6" build completely disabling fractional scaling for the Xdcv use case (on apply and revert), but not including the "zero hz" fix? This way we would be able to validate item 1 above (even if we see the zero hz bogus messages, which we can ignore for now). If this succeeds, we can investigate the item 3 above separately, so we can then re-introduce the "zero hz" fix. [1] https://pastebin.ubuntu.com/p/Xtyfvb3CV2/ -- 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
