As a workaround I found this GNOME extension: https://extensions.gnome.org/extension/517/caffeine/
If you go into F11 fullscreen during playback, the screen no longer blanks. :-) -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1697373 Title: [screensaver] Screen blanks during video playback in Chrome and Firefox under Xwayland Status in xorg-server package in Ubuntu: Triaged Bug description: gnome-shell / gdm / wayland Test Case: 1. Launch netflix in chrome 2. Play a video 3. Wait until the display times out. Expected result The screen does not dim Actual result The display goes black. ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: gnome-shell 3.24.2-0ubuntu6 ProcVersionSignature: Ubuntu 4.10.0-22.24-generic 4.10.15 Uname: Linux 4.10.0-22-generic x86_64 ApportVersion: 2.20.5-0ubuntu4 Architecture: amd64 CurrentDesktop: GNOME Date: Mon Jun 12 09:21:46 2017 DisplayManager: gdm3 InstallationDate: Installed on 2013-09-03 (1377 days ago) InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Alpha amd64 (20130902) ProcEnviron: TERM=screen-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=fr_FR.UTF-8 SHELL=/bin/bash SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1697373/+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
