Some PCs still turn off the backlight by zero brightness even when the maximum brightness level is less than 100

[Shih-Yuan Lee]

Need to have fix in Bionic, better to have it in xenial.

The minimum brightness of the laptop screen panel may not be realistic sometimes especially when having a problematic screen panel.

For example, Dell Precision 5720 AIO only has 9 levels in /sys/class/backlight/intel_backlight/max_brightness because the wrong settings in VBIOS. It is an all-in-one desktop PC and there is no brightness hotkey to control the backlight. When we set 0 to /sys/class/backlight/intel_backlight/brightness, it turns off the panel's backlight and there is no way to brightness up the backlight again so we can only avoid using 0 as the minimum backlight level.

[Shih-Yuan Lee (fourdollars)]

This patch is for gnome-settings-daemon, but it has been rejected by Bastien Nocera [gnome-settings-daemon developer].

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Avoid using zero brightness by settings." seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Will Cooke (willcooke)]

Added to Trello: https://trello.com/c/DdHQRncy/20-bug-1691032-some-pcs-still-turn-off-the-backlight-by-zero-brightness-even-when-the-maximum-brightness-level-is-less-than-100