Access /sys/class/backlight/.. by user (not root)

Technical Support
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1

How to set permanent file write permissions for /sys/class/backlight/backlight/bl_power
in order to allow user (not root) to power on/off the display?
User has no permissions and sudo is not available?

Is there a possibility to set file permissions upon boot (i.e. chmod g+w /sys/class/backlight/backlight/bl_power) in order to make them ‘permanent’?

Thanks for feedback.

2

Hi @stegd

Concerning your question, what is your application?
Which display are you using?

Best regards,
Jaski

3

It’s a doorsign application with a lcd display (rgb/lvds interface).

Please note that with root everything works: display on/off with
echo 1 > /sys/class/backlight/backlight/bl_power
echo 0 > /sys/class/backlight/backlight/bl_power

But user is missing permanent file write permissions. Any idea how to solve?

Best regards

4

hi @stegd

I think you need to create udev rules. Please have a look at these two links: Link1 and Link2.

Best regards,
Jaski