I am trying to set up backlight controls, but cannot find a way to make it work.
By default I have /sys/class/backlight/acpi_video0
, but that does not respond to my brightness settings.
Knowing that I'm on a Intel NUC, obviously there are Intel Graphics installed:
$ sudo lshw -C display
*-display
description: VGA compatible controller
product: Iris Plus Graphics 655
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 01
width: 64 bits
clock: 33MHz
capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:131 memory:bf000000-bfffffff memory:80000000-8fffffff ioport:4000(size=64) memory:c0000-dffff
And that makes me think that instead of acpi_video0
, I should have a intel_backlight
option.
I have tried to use kernel parameters:
acpi_backlight=vendor
- does not help, removed theacpi_video0
, but didn't provide anything in place.video.use_native_backlight=0
-Jun 05 16:35:41 busmatic13 kernel: video: unknown parameter 'use_native_backlight' ignored
- same with
video.use_native_backlight=1
Tried to install xserver-xorg-video-intel
- didn't help.
At first I tried to work with the native xbacklight
utility, but that errored out: No outputs have backlight property
.
Then I set up acpilight
, while it did change values, it didn't update anything on the actual display.
UPDATE: This is to control an external monitor!
External monitors lack hardware brightness control through the cable. You can use the controls on the monitor or through software:
This will give 85% brightness. To get MONITOR_NAME use:
ddcutil
does the magic: