amd64/181357: LCD Brightness Control not working on Lenovo X121e (ACPI issue?)

Jan Bramkamp crest at rlwinm.de
Wed May 7 20:14:08 UTC 2014


On 07.05.2014 02:00, Miguel Clara wrote:
> The following reply was made to PR amd64/181357; it has been noted by GNATS.
> 
> From: Miguel Clara <miguelmclara at gmail.com>
> To: bug-followup at freebsd.org, matthias at petermann-it.de
> Cc:  
> Subject: Re: amd64/181357: LCD Brightness Control not working on Lenovo X121e
>  (ACPI issue?)
> Date: Wed, 7 May 2014 00:57:33 +0100
> 
>  --047d7bae487e1f0c3d04f8c4041c
>  Content-Type: text/plain; charset=UTF-8
>  
>  I get the same issue with an acer laptop!
>  
>  xbacklight gives me:
>  
>  No outputs have backlight property
>  
>  I had no luck with acpi_call though (and I've tried loading several acpi_
>  modules with no luck)
>  
>  only workaround I have is:
>  
>  xrandr --output LVDS1 --brightness 0.9

I ran into similar problem with a X220. The ACPI brightness control can
only be called directly with acpi_call. I bound the acpi_ibm brightness
up/down events to a shell script using acpi_call with devd. It wroks
except that the screen always turns on with maximum brightness if
backlight had been deactivated by DPMS. I haven't found any convenient
event to hook with devd for this case.


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