19 Nov
2016
19 Nov
'16
8:35 a.m.
On Sat, 19 Nov 2016 02:00:11 -0600 "David C. Rankin" <drankinatty@suddenlinkmail.com> wrote:
[snip a whole bunch of maundering]
xrandr does not adjust the backlight. It adjusts the brightness, which while it may have the same visible effect may have negative effects on battery life and component wear compared to proper backlight adjustment. acpi_backlight=vendor is the default, acpi_backlight=none is invalid. The option you are looking for is acpi_backlight=video, which takes the backlight control away from the vendor driver and hands it back over to the standard ACPI backlight driver. This will generally solve the issue you are having. ~Celti