I'm running Debian 8.8 on my Acer Aspire Timeline X and I can't seem to adjust the screen brightness with the normal keys.
It would usually adjust with the 'Fn' key and the arrows '< >'. When I do this, I get the pop up with the slider adjusting, but the actual screen brightness isn't changing.
I can actually go into the files:
/sys/class/backlight/intel_backlight/brightness
and adjust it from there on leafpad.
Why don't the buttons work?
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[SOLVED]Can't adjust screen brightness with keys
[SOLVED]Can't adjust screen brightness with keys
Last edited by ellescer on 2017-05-25 02:23, edited 1 time in total.
Re: Can't adjust screen brightness with keys
What desktop environment are you using? Are there any other interface folder in /sys/class/backlight/ other than intel_backlight?ellescer wrote:I can actually go into the files:
/sys/class/backlight/intel_backlight/brightness
and adjust it from there on leafpad.
If you are using GNOME and there are indeed other interface folder in /sys/class/backlight/, such as acpi_video0,it might be that G-S-D is trying to adjust the wrong interface since it has the following preference:
firmware(acpi_video0) -> platform(acer_wmi) -> raw(intel)
In this case, you might try tweaking related kernel parameters to try to make one of the interfaces to disappear. Relevant kernel params are:
acpi_backlight=vendor
acpi_osi=Linux
acpi_osi=
acpi_backlight=vendor acpi_osi=Linux
acpi_backlight=vendor acpi_osi=
acpi_backlight=intel
acpi_backlight=intel acpi_osi=
acpi_backlight=intel acpi_osi=Linux
... ...
(other possible settings or combinations)
If the above does not work, you can try other common workarounds such as dropping configuration in xorg.conf as described in https://askubuntu.com/a/841903
Re: Can't adjust screen brightness with keys
I am using Xfce, and there actually is another interface folder in their, "acpi_video0".orythem27 wrote:What desktop environment are you using? Are there any other interface folder in /sys/class/backlight/ other than intel_backlight?
If you are using GNOME and there are indeed other interface folder in /sys/class/backlight/, such as acpi_video0,it might be that G-S-D is trying to adjust the wrong interface since it has the following preference:
firmware(acpi_video0) -> platform(acer_wmi) -> raw(intel)
How would I go about accessing those kernel parameters?
Re: Can't adjust screen brightness with keys
Then you may first try something like "acpi_backlight=none".ellescer wrote:I am using Xfce, and there actually is another interface folder in their, "acpi_video0".
Edit /etc/default/grub and add kernel params in GRUB_CMDLINE_LINUX_DEFAULT. e.g.ellescer wrote:How would I go about accessing those kernel parameters?
Code: Select all
GRUB_CMDLINE_LINUX_DEFAULT="splash acpi_backlight=none"
Re: Can't adjust screen brightness with keys
Different computer but, I use:
Code: Select all
acpi_backight=video
ASRock H77 Pro4-M i7 3770K - 32GB RAM - Pioneer BDR-209D
Re: Can't adjust screen brightness with keys
There's one that has this:orythem27 wrote:Edit /etc/default/grub and add kernel params in GRUB_CMDLINE_LINUX_DEFAULT. e.g.
Code: Select all
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
EDIT: Yes! I finally got it to work by doing
Code: Select all
GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor"