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frangio

Member

Registered: 2015-11-20

Posts: 7

acpid sometimes not receiving button/brightness(up/down) events

My laptop has two brightness keys that generate the ACPI events button/brightnessdown and button/brightnessup.

However, sometimes after booting these events are not generated. They do not show up in acpi_listen, but the keypresses show up in xev (as XF86MonBrightnessDown and XF86MonBrightnessUp). Once I run "systemctl restart acpid" the events show up as expected.

It's non-deterministic, though. On some runs they immediately work after booting. Could this be a problem with the order in which services are run? The acpid service I'm using is the one provided by the acpid package.

These two keys are the only affected ones. Volume button events as well as video/switchmode are always generated.

I have set up the following rule and handler, but I suspect it's irrelevant.

$ cat /etc/acpi/events/brightness 
event=video/brightness(down|up)
action=/etc/acpi/brightness.sh %e
$ cat /etc/acpi/brightness.sh 
#!/usr/bin/bash

step=10

bl=/sys/class/backlight/intel_backlight

sstep=$(($(< $bl/max_brightness) * $step / 100))

case "$1" in
    video/brightnessup)
        echo $(($(< $bl/brightness) + $sstep)) > $bl/brightness
        ;;

    video/brightnessdown)
        echo $(($(< $bl/brightness) - $sstep)) > $bl/brightness
        ;;
esac

Last edited by frangio (2016-03-11 04:52:43)

frangio

Member

Registered: 2015-11-20

Posts: 7

Re: acpid sometimes not receiving button/brightness(up/down) events

I would appreciate some help on how to debug this issue.