Arch Linux

Aeronaelius

Member

Registered: 2017-01-06

Posts: 13

Screen backlight brightness on Dell XPS 15 9550

I had an issue during boot concerning screen brightness on my Dell XPS 15 9550. I managed to solve it and I would like to share the experience for those who might need it.

I followed this guide for installing Arch on my laptop. There it is suggested to add

acpi_backlight=vendor acpi_osi=Linux

as kernel parameters to fix backlight control. However, on boot I would get this error

[FAILED] Failed to start Load/Save Screen Backlight Brightness of backlight:dell_backlight.
See 'systemctl status systemd-backlight@backlight:dell_backlight.service' for details.

Regardless, my backlight control was working fine with both keys and slider. Seeing the error on boot did annoy me and therefore I tried to resolve it. For me, changing the kernel parameters to either one of the following resolves the issue:

acpi_backlight=native acpi_osi=Linux

acpi_backlight=video acpi_osi=Linux

acpi_osi=Linux

Not adding anything at all is also a solution. Good luck!

comnbatrock

Member

Registered: 2017-02-14

Posts: 17

Re: Screen backlight brightness on Dell XPS 15 9550

I had this issue on a zenbook which i couldn't fix with your solution ( i tried ). my solution was to update to the latest development kernel (linux-mainline) on it's current version (4.10rc8) it fixes a lot of those issues. You can compile it yourself, there's also a precompiled version available on unofficial repos. I expect it will be released soon though and available via normal means