On 05/17/2017 06:08 PM, Rob Owens wrote:
> On Wed, May 17, 2017 at 8:48 AM, Lars Noodén <lars.nooden@???> wrote:
>
>> On 05/04/2017 03:42 PM, Lars Noodén wrote:
>>> I'm having trouble adjusting the backlight on my LCD screen in RC 1 with
>>> XFCE4. No matter what I've tried so far, it stays where it is. With
>>> Ubuntu 16.04, things are pre-configured and it is just a matter of
>>> pressing the right function buttons. However, with Devuan Jessie RC 1
>>> the right commands are hard to figure out.
>>>
>>> Here is what I've tried so far to change the backlight intensity. None
>>> have any effect:
>>>
>>> $ xrandr --output default --brightness 0
>>> xrandr: Gamma size is 0.
>>
>
> I did this just yesterday on a laptop running Funtoo with Fluxbox, where
> the built-in function keys for dimming did not work. But I specified a
> decimal, like this:
>
> xrandr --output default --brightness .7
>
> That worked for me. Maybe the problem is that you specified zero for the
> brightness.

Thanks for the reply. It seems that I cannot get anywhere with xrandr
on my system:

$ xrandr --output default --brightness .7
xrandr: Gamma size is 0.
$ xrandr --output default --brightness .1
xrandr: Gamma size is 0.
$ xrandr --output default --brightness .9
xrandr: Gamma size is 0.
$ xrandr --output default --brightness 1.9
xrandr: Gamma size is 0.
$ xrandr --output default --brightness 2
xrandr: Gamma size is 0.
$ xrandr --current
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00*

Are there any preparations that need to be made first?

Regards,
Lars