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#1 2018-12-17 21:53:55

myscha
Member
Registered: 2018-12-17
Posts: 6

[Solved] Backlight change only after resume from standby

Hello,

I was using Arch for quite some time on a Lenovo T61 and these days I installed Arch with Plasma on a Lenovo T540p with Intel only graphics. I managed to get almost anything to work so far except the behaviour of the display brightness:

  • After a reboot the brightness indicator responds to the according key presses, but the brightness doesn't change. Also the value in  /sys/class/backlight/intel_backlight/brightness  changes as I'd expect. Bringing the value to 0 makes it dark, but anything else results in full brightness.

  • After closing and re-opening the Laptop lid the brightness indicator and  /sys/class/backlight/intel_backlight/brightness  seem to behave like before, but now the brightness really changes.

I already passed  acpi_osi=linux  and  acpi_backlight=video/vendor/native  to the kernel but without any effect.
I tried adding  Option      "Backlight"  "intel_backlight"  to  /etc/X11/xorg.conf.d/20-intel.conf  but this also didn't help.

My  /etc/modprobe.d/i915.conf  contains

options i915 fastboot=1
options i915 enable_gvt=1

# don't load the nVidia driver
blacklist nouveau

What else could I try to get that working?


SOLUTION:

options i915 fastboot=1

leads to this behaviour. After removing it from  /etc/modprobe.d/i915.conf  everything works as expected.

Last edited by myscha (2018-12-19 21:31:53)

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