I did some experimenting. The wayland gnome-shell crash and monitor power-saving issue seems to be limited to a hdmi connection, and has something to do with the monitor searching for a signal on other inputs after it has been blanked.
I dug out an old d-sub vga cable and connected the monitor to the graphics card with that. Timed blanking of the screen or locking the desktop manually did not cause a gnome-shell crash on wayland when using the d-sub cable. Monitor power saving worked as expected. The next thing I tried was reconnecting the hdmi cable and locking the monitor to the hdmi input and turning off the automatic signal selection. With the monitor configured that way, both timed blanking and manual locking of the desktop worked as expected. The monitor successfully went to sleep and the session resumed after user input. I also tried plugging in a tv using hdmi. That didn't produce any session crashes. However the tv makes no attempt to blank itself or enter a power-saving mode; it just stays on with a "No Signal" notice. I also connected an old 1680x1050 monitor using a dvi cable. That simply refused to boot past the Ubuntu splash screen. However the same monitor works perfectly when booting into the 17.10 beta live-cd, but the live-cd runs on a xorg session and not wayland. Next I connected that same old monitor using dvi together with the newer dell over hdmi simultaneously, and booted successfully into a wayland session. (That this combination actually worked and booted barely makes sense. Also the primary monitor was changed between login prompt and the desktop being loaded, but whatever...) With multiple monitors connected timed blanking or desktop locking did not crash the gnome-shell session, but they still did not blank properly. After blanking both screens, they were immediately both turned on again with a only a black background and the mouse cursor on the primary monitor. And that is how they stayed, with backlights both still on. No blanking or power-saving was done thereafter. Mouse or keyboard input would return the lock-screen to the displays and unlocking with a password would successfully return the active user session. Lastly, after again locking the dell monitor to the hdmi input and turning off the automatic signal selection, both monitors would successfully enter power-saving modes and the user session could be resumed after unlocking with a password. TL;DR = It seems that the monitor disconnecting itself from the blanked/inactive hdmi input in order to search for an active vga input signal is what is triggering the gnome-shell crash and/or preventing the monitor from entering its power-saving mode. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1722353 Title: Screen blanking and/or screen lock crashes gnome-shell user session on wayland - Ubuntu 17.10 beta To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1722353/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
