[screensaver] Screen blanks during video playback in Chrome and Firefox under Xwayland

gnome-shell only knows that Chrome/Chromeium is running. It does not know what the browser is doing.

So if you want to disable blanking specifically during video playback, that's a browser enhancement. You might need to log a bug directly with Chromium/Chrome upstream.

The behaviour is different in unity7 and gnome-shell. In unity7 screen blanking is disabled during video playback. Tested on the same machine with same settings.

On unity7 I did the following test:
1. Set screen blanking to 2 min
2. Wait 2 min with nothing playing
  -> The display goes black after 2 min
3. Play a netflix video in Chrome
  -> The display does not go black after 2 min

Oh... probably a duplicate of bug 1692762 :)

I am not sure it is a duplicate because I am using GDM

Sorry, that's the opposite of your problem :)

Back on topic with this bug...

I don't know what API(s) are being used by the browser to disable video playback, but there are only a few probable options:

  (a) The API is different between telling Unity7 and Gnome Shell to not blank, and Chrome doesn't support the latter; or
  (b) The API is different between telling Unity7 and Gnome Shell to not blank, and Chrome does support both but gnome-shell is ignoring it; or
  (c) The API is the same for both Unity7 and Gnome Shell, and gnome-shell is ignoring it.

So yeah, in both (b) and (c) we would need a gnome-shell task. But there are many possible reasons as to why this is broken. Needs more research.

Status changed to 'Confirmed' because the bug affects multiple users.

It appears that Xwayland on artful has no DPMS support yet:

https://cgit.freedesktop.org/xorg/xserver/tree/Xext/dpmsstubs.c?h=server-1.19-branch
https://cgit.freedesktop.org/xorg/xserver/tree/hw/xwayland/Makefile.am?h=server-1.19-branch

So Chromium can't use DPMS to disable blanking:

https://chromium.googlesource.com/chromium/src.git/+/master/device/power_save_blocker/power_save_blocker_x11.cc#427

Looks like the situation is changing in trunk Xorg/Xwayland but unclear what the status of DPMS support is (dpmsstubs.c no longer exists).

Assigned to xorg-server because the feature simply does not exist in Xorg/Xwayland 1.19.

Either Xwayland (source: xorg-server) needs enhancement to support DPMS, or Chromium needs enhancement to use something other than DPMS.

chromium 61.0.3163.31 (from the beta channel) still affected.

Relevant Chromium bug is #783737: https://bugs.chromium.org/p/chromium/issues/detail?id=783737

I confirm that also happens in firefox 57 on Ubuntu 17.10.

Firefox: 57.0
Ubuntu: 17.10
Gnome-shell 3.26.2
xwayland:2:1.19.5-0ubuntu2

PS I noticed there is a '-v' option for wayland that runs with "screen-saver without video blanking". Is that helpful?

From what I can tell, Xwayland is still missing DPMS support:
https://cgit.freedesktop.org/xorg/xserver/tree/hw/xwayland/

And that's still what all X apps need to use. For example:
https://chromium.googlesource.com/chromium/src.git/+/master/services/device/wake_lock/power_save_blocker/power_save_blocker_x11.cc

This is a bug in Xwayland only. Xwayland needs to be modified to convert DPMS requests from clients like web browsers into calls to this:
https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/idle-inhibit

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. :-)

Still happpening in Ubuntu 18.04. Maybe not that important now that wayland is not the de default session, but nonetheless worth of fixing I think

its problem with vlc as well; I'm neither using wayland.

Still there with Ubuntu 19.10.

yah it affects my new installation of ubuntu 18.04 lts

Yes, cannot watch video without display locking

Having this issue on Xubuntu 19.10

Having this issue on Lubuntu 20.04.1 as well.

Ubuntu hirsute hippo too