[Bug 1840592] Re: systemd-backlight does not save and restore brightness for nvidia display

[Kai-Heng Feng]

The backlight device only gets registered after it's opened by graphical
session.

And the backlight gets unregistered when graphical session stops, hence
when systemd-backight at .service's "Conflicts=shutdown.target" triggers,
the backlight is already gone so the brightness wasn't saved.

Since it's not saved, the backlight won't be restored for next boot.

The easiest approach is to let nvidia driver always registers the
backlight device.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1840592

Title:
  systemd-backlight does not save and restore brightness for nvidia
  display

Status in nvidia-graphics-drivers package in Ubuntu:
  New
Status in nvidia-graphics-drivers-418 package in Ubuntu:
  New
Status in nvidia-settings package in Ubuntu:
  New
Status in systemd package in Ubuntu:
  New

Bug description:
  Running nvidia gtx 1080 graphics card, with proprietary nvidia drivers
  on ubuntu 19.04. I can change screen brightness from 0% to 100% in 5%
  steps. However, after a reboot or after a shutdown, brightness level
  reverts to 100%. Please fix to is "remembers" the current brightness
  value at shutdown time, like in does Windows.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/1840592/+subscriptions