Arch Linux

yzsolt

Member

Registered: 2014-10-23

Posts: 1

Dell 5737 backlight problems

Hi,

I have a Dell Inspiron 5737 17R laptop with Intel HD4400 graphics (and a dedicated Radeon card, but it doesn't matter now). The problem is, backlight setting has broken after an update. If I remember correctly, it was the 3.15 -> 3.16 kernel update.
With the 3.15 kernel there was an acpi0 and an intel backlight in /sys/class/backlight, and with some tweaking (adding video.use_native_backlight parameter for boot, etc.) I got brightness control working perfectly.
The problem is, after the 3.16 update there is a new dell_backlight entry in /sys/class/backlight beside intel_backlight, and it registers itself as a backlight type "platform", while the Intel one is "raw". There would be no problem if setting the values in dell_backlight would work, but changing them have no effect, and since Gnome (and everything which uses the code found in libbacklight.c) prefers "platform" type backlight over "raw", I don't have convenient way to change backlight currently (of couse setting the values in intel_backlight through terminal works).

My question is, can I fix (or disable) dell_backlight somehow?

EDIT: solution found. Disabling the dell_laptop kernel module solves the problem. It seems somebody (tried) to add a module setting to solve this problem, see: patch, but it doesn't seem to be merged. I hope nothing serious stopped working with disabling this module, fortunately function keys are still working.

Last edited by yzsolt (2014-10-23 12:01:56)