Re: how to turn off backlight in console (without any X server)

Hi and thanks for your ideas

Unfortunately there is no directory /sys/class/backlight on my system.

After a

locate backlight

I juste had the following files as seemingly relevant.

/var/lib/systemd/backlight/pci-0000:02:00.0:backlight:nv_backlight
/var/lib/systemd/backlight/platform-applesmc.768:leds:smc::kbd_backlight

Which were both at 100 but an echo 0 > .... had no effect on the backlight (tough it tuned to 0 the value of in the files )

Any ideas where I should start to look at ?

Cheers,

2016-11-01 14:49 GMT+01:00 <tomas@tuxteam.de>:

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On Tue, Nov 01, 2016 at 02:22:46PM +0100, Laurent Debian wrote:
> Hi all,
>
> I would like to turn off the backlight completly on a mac book pro 2008
> (sid).
> I don't have any x server. Does it explains this error ?

Most probably yes. "Xbacklight" hints at an X application. RandR is an
X server extension.

> > xbacklight -set 10
> > RANDR Query Version returned error -1
> >
>
> the graphic card is
> 02:00.0 VGA compatible controller: NVIDIA Corporation C79 [GeForce 9400M]
> (rev b1)
> nouveau is loaded by the kernel.

I'd imagine that xbacklight (and xrandr) try to talk to the X server to
do their bidding.

>
> Any way to turn off the backlight without installing X woudl be greatly
> appreciated.

Have a look at the files under /sys/class/backlight. For me, this works:

sudo bash -c "echo 2 > /sys/class/backlight/acpi_video0/brightness"

Enjoy

- -- t
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