Bug#971569: mutter: Laptop display stays dimmed after blanking screen under wayland

[Jaycee Santos]

Package: mutter
Version: 3.38.0-2
Severity: normal
X-Debbugs-Cc: jlsantos at protonmail.com

On a Thinkpad X220, I have GNOME set to dim the screen when inactive, with
blank screen enabled.

When the screen is blanked after inactivity (display turns off), interacting
with the laptop turns on the screen but does not reset the brightness level.
(It stays dimmed and the brightness slider does not match the brightness
level of the display.)

The user would have to adjust the brightness (each time the laptop screen
is blanked) or connect the laptop to power, to free the display from the
dimmed state.

This is reproducible when using GNOME/mutter under Wayland _and_ on battery
power with "Dim Screen When Inactive" enabled. This does not happen when
plugged in.
I have not been able to reproduce this bug when running GNOME/mutter under
Xorg.



-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.8.0-2-amd64 (SMP w/4 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages mutter depends on:
ii  adwaita-icon-theme            3.38.0-1
ii  gnome-settings-daemon-common  3.38.0-2
ii  gsettings-desktop-schemas     3.38.0-2
ii  libc6                         2.31-3
ii  libgles2                      1.3.2-1
ii  libglib2.0-0                  2.66.0-2
ii  libmutter-7-0                 3.38.0-2
ii  libwayland-server0            1.18.0-2~exp1.1
ii  libx11-6                      2:1.6.12-1
ii  libxcomposite1                1:0.4.5-1
ii  mutter-common                 3.38.0-2
ii  zenity                        3.32.0-5

mutter recommends no packages.

Versions of packages mutter suggests:
ii  gnome-control-center  1:3.38.0-2
ii  xdg-user-dirs         0.17-2

-- no debconf information