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techforay

Member

Registered: 2021-03-08

Posts: 17

Function F8 brightness decrease doesnt work on lenovo thinkpad

I use the sxhkdrc file to establish keybindings.  I have brightnessctl installed.

In my sxhkdrc i have the following commands

XF86MonBrightnessDown
brightnessctl set 10%-

XF86MonBrightnessUp
brightnessctl set 10%+

The increase works but the decrease does not. can someone tell me why?

Last edited by techforay (2023-08-02 22:12:46)

ectospasm

Member

Registered: 2015-08-28

Posts: 302

Re: Function F8 brightness decrease doesnt work on lenovo thinkpad

What model ThinkPad do you have?  There are many ThinkPad models listed in the Arch Wiki, if you find your model it may have clues about this. 

Off the top of my head, though, most times the postive ('+') and negative ('-') modifiers typically come before, not after the percentage.  I.e.:

brightnessctl set +10%
brightnessctl set -10%

But then again I'm not sure about sxhkdrc, and I'm not sure if brightnessctl works with your model ThinkPad (since you didn't specify it).

jl2

Member

From: 47° 18' N 8° 34' E

Registered: 2022-06-01

Posts: 1,248

Re: Function F8 brightness decrease doesnt work on lenovo thinkpad

Can you manually set the brightness in '/sys/class/backlight'?

And take a look at https://wiki.archlinux.org/title/Backlight

Else, use xorg-xev or web to check if the key works.

Last edited by jl2 (2023-08-05 07:58:23)

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snakeroot

Member

Registered: 2012-10-06

Posts: 175

Re: Function F8 brightness decrease doesnt work on lenovo thinkpad

Off the top of my head, though, most times the postive ('+') and negative ('-') modifiers typically come before, not after the percentage.  I.e.:

brightnessctl -h specifies that decrement should come after (10%-) and increment before (+10%)

Valid values:
   percentage delta		Example: 50%- or +10%

However, by experimentation, it's actually more permissive than that since increment (+) works either before or after and only decrement before (-20%) throws an error.

ectospasm

Member

Registered: 2015-08-28

Posts: 302

Re: Function F8 brightness decrease doesnt work on lenovo thinkpad

brightnessctl -h specifies that decrement should come after (10%-) and increment before (+10%)

Valid values:
   percentage delta		Example: 50%- or +10%

That actually makes sense, whatever options library they're using isn't configured to accept -10%, because either the developer was lazy or doesn't know how to treat that as a valid parameter value (it thinks it's an option flag).  It may work if you put -- -10% as the last item of the command, but not really sure.

You still haven't said what model ThinkPad you have, there are likely clues to this on the particluar model page on the Wiki.