[SOLVED]Udev rule to change brightness on charger removal/insertion

CarterCox · 2018-06-08 04:12:54

Hi guys. I am following this guide, because I want to create udev rules so that every time I insert my AC charger to my laptop, this commands is excecuted:

 /usr/bin/change_brightness.sh
echo "2368695" > /sys/class/brightness/intel_backlight/brightness

And whenever I disconnect it, this one is:

 /usr/bin/change_brightness_low.sh
echo "1000000" > /sys/class/brightness/intel_backlight/brightness

So

/etc/udev/rules.d/10-local.rules
KERNEL=="something", ATTR{connected?}=="yes", RUN+="/usr/bin/change_brightness.sh"
KERNEL=="something", ATTR{connected?}=="no", RUN+="/usr/bin/change_brightness_low.sh"

Where "something" would be the name of the the charger and the ATTR and "yes" and "no" would indicate the status of it (maybe, I don't know, this is hypothetical to make my point).
I know I am supposed to find this using

udevadm info -a -p /sys/path/to/device

But I have no idea what this /path/to/device is.
Does anyone know what the possible path could be?
Thanks!

Solution:

/usr/bin/change_brightness.sh

 #!/bin/bash
sleep 2s
echo "2000000" > /sys/class/backlight/intel_backlight/brightness

/usr/bin/change_brightness_low.sh

#!/bin/bash
sleep 2s
echo "1000000" > /sys/class/backlight/intel_backlight/brightness

/etc/udev/rules.d/99-local.rules

ACTION=="change", SUBSYSTEM=="power_supply", ATTR{online}=="1", RUN+="/usr/bin/change_brightness.sh"
ACTION=="change", SUBSYSTEM=="power_supply", ATTR{online}=="0", RUN+="/usr/bin/change_brightness_low.sh"

Last edited by CarterCox (2018-06-08 21:13:47)

x33a · 2018-06-08 04:43:36

Try /sys/class/power_supply

seth · 2018-06-08 05:45:55

You're aware that there's even a backlight centric udev example on https://wiki.archlinux.org/index.php/Udev ?

CarterCox · 2018-06-08 11:14:40

@x33a: Yes! That's it! Thanks!

@seth: No, you mean this one?

seth · 2018-06-08 11:29:19

No. Press ctrl+f and search the page for "backlight"…

CarterCox · 2018-06-08 18:14:55

@seth: Oh, yeah, I used that example to create mine. I didn't know the values would be the same.

However, it doesn't seem to be working now. This is what I did so far: https://forumshare.duckdns.org/Arch/

I even added a wait time so it will wait for the BIOS changes and then override them.

Last edited by CarterCox (2018-06-08 20:14:21)

seth · 2018-06-08 18:41:36

Did you "udevadm control --reload"?

CarterCox · 2018-06-08 19:29:00

@seth: No, I just rebooted. I just tried that and it still doesn't work. I want to clarify that the scripts do change the brigthnless when excecuted alone, so the problem is not there. I increased the sleep time but still doesn't work.

seth · 2018-06-08 19:35:06

That's sufficient.
You should add sth. like "echo foo > /tmp/bar" to ensure they're invoked at all.
Also try "udevadm test /sys/class/power_supply/" and check your journal for errors.

I cannot immedidately spot issues w/ the stuff you posted…

CarterCox · 2018-06-08 20:20:58

Ok @seth, thanks for taking the time to review this.
Good suggestion on the journal check. There are actually some errors. Here: https://forumshare.duckdns.org/Arch/journal_udev.txt Also: https://forumshare.duckdns.org/Arch/cha … ess.sh.txt .

seth · 2018-06-08 20:34:30

Thanks for the individual files. Now google "shebang" ;-)

CarterCox · 2018-06-08 21:07:31

seth wrote:

Thanks for the individual files. Now google "shebang" ;-)

You know... I actually saw the "shebang" thing here: http://www.reactivated.net/writing_udev … ternal-run , but I thought it was only for scripts per se (like "if" ... "fi"). I can't believe that was the error.

Thanks a lot seth!

Edit: Updated OP to reflect the solution.

Last edited by CarterCox (2018-06-08 21:11:03)

Arch Linux

#1 2018-06-08 04:12:54

[SOLVED]Udev rule to change brightness on charger removal/insertion

Solution:

#2 2018-06-08 04:43:36

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#3 2018-06-08 05:45:55

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#4 2018-06-08 11:14:40

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#5 2018-06-08 11:29:19

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#6 2018-06-08 18:14:55

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#7 2018-06-08 18:41:36

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#8 2018-06-08 19:29:00

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#9 2018-06-08 19:35:06

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#10 2018-06-08 20:20:58

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#11 2018-06-08 20:34:30

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

#12 2018-06-08 21:07:31

Re: [SOLVED]Udev rule to change brightness on charger removal/insertion

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