Getting screen brightness in a Linux kernel module

Question

I'm trying to get current screen brightness in my Linux kernel module. However, I don't know how can I access the brightness variable, though easily get it in an user-space application using the sysfs interface.

Please let me know a clue about this problem.

Thank you.

If you are into kernel module programming, peeking at the sysfs filesystem code should not be that hard. — Paulo Scardine, Sep 07 '12 at 07:03
Yeah. I'm doing now, but I could not find any clues because I'm a newbie in kernel module programming. — Brian, Sep 07 '12 at 07:28

score 2 · Answer 1 · answered Sep 07 '12 at 09:32

Usually modern Desktops (GNOME/XFCE4/KDE) provide utilities to change the brightness but answering your question you should look on your /sys/class directory for it. HINT: look for backlight you will find one driver which provides you that functionality.

In my case it is samsung-laptop module and intel.

score 1 · Answer 2 · answered Oct 06 '21 at 01:30

1

For me

/sys/class/backlight/intel_backlight
$ cat actual_brightness

This worked to get the actual brightness.You might want to go to /sys/class/backlight and try to ls to see whats in store.

answered Oct 06 '21 at 01:30

Savannah Madison

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score 0 · Answer 3 · edited Dec 08 '21 at 12:03

0

You can change directory to /sys/class/backlight/acpi_video0 and then open actual_brightness file.

cd /sys/class/backlight/acpi_video0
cat actual_brightness

edited Dec 08 '21 at 12:03

Mr Kashyap

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answered Dec 07 '21 at 17:28

XsOuLp

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Getting screen brightness in a Linux kernel module

3 Answers3