Aurko Roy [2012.08.15 1140 +0530]:
On Wed, Aug 15, 2012 at 7:00 AM, Michael Nawrocki <zaedrake@gmail.com>wrote:
Hey everyone,
I'm trying to get my laptop backlight keys (fn+f6/f7) to adjust the brightness of my toshiba laptop backlight. Previously, I had entered the following in my /etc/acpi/handler.sh to handle the acpi events generated when those keys were pressed:
video/brightnessdown) echo $(($(cat /sys/class/backlight/acpi_video0/brightness) -1)) > /sys/class/backlight/acpi_video0/brightness ;;
video/brightnessup) echo $(($(cat /sys/class/backlight/acpi_video0/brightness) +1)) > /sys/class/backlight/acpi_video0/brightness ;;
However, as I am working on migrating to systemd, acpid no longer runs and hence does not handle these events. How can I write a similar handler into systemd?
Thanks,
Mike
I used to reduce my brightness using a similar command in /etc/rc.local (/bin/echo -n 0 > /sys/class/backlight/acpi_video0/brightness) but for the reasons that you mention this won't work anymore. I then switched to using X's brightness handler (xbacklight -set 0) which reduces display brightness as X starts. This is an easy solution but only works if you use X or if the delayed reduction in brightness is acceptable to you.
You can achieve the same by adding the instructions to write to /sys/class/backlight/acpi_video0/brightness to an appropriate file in tmpfiles.d. Read the section on temporary files in the systemd page on the archwiki. Cheers, Norbert