Re: Fn keys not working in Debian 12 on Lenovo Thinkpad T450s

[Rodolfo Medina <rodolfo.medina@gmail.com>]

<tomas@tuxteam.de> writes:

> On Thu, Jan 11, 2024 at 08:53:46AM +0000, Rodolfo Medina wrote:
>> As my machine has a dual boot with MS Windows, F2 and F3 keyboard keys work
>> fine in Windows in lowering and increasing sound volume, and F1 for muting it
>> etcetera F4, F5, F6..., but in Debian they don't seem to work.
>
> "In Debian" is a wide land :-)

It's Bookworm with Openbox.


> OT1H...
>
> A week ago I installed Debian's Bookworm with MATE on a friend's computer
> (Thinkpad x270) and the loudness keys worked out of the box.
>
> OTOH...
>
> Myself -- I have no desktop environment (fvwm on X, *no* systemd, *no*
> DBUS, so that would count as "exotic guy").
>
> On my laptop (a Thinkpad x230) the background brightness wasn't working
> (I don't know about the loudness things, since I never needed/used them).
>
> Therefore I decided to catch ACPI events and set up this:
>
> --- ---
> tomas@trotzki:~$ cat /etc/acpi/events/briteup
>
> event=video/brightnessup
> action=/etc/acpi/actions/brite "%e"
> --- ---
> tomas@trotzki:~$ cat /etc/acpi/events/britedn
>
> event=video/brightnessdown
> action=/etc/acpi/actions/brite "%e"
> --- ---
> tomas@trotzki:~$ cat /etc/acpi/actions/brite 
>
> #!/bin/sh
> logger "[ACPI] $@"
> BASE="/sys/class/backlight/intel_backlight"
> CURR=$(cat "$BASE/brightness")
> MAX=$(cat "$BASE/max_brightness")
> # MIN is some arbitrary "low" value. Note that for values
> # of MIN below 6 (more precisely: 2/11 for our factor), the
> # thing gets stuck at the low end: (13 * x) / 11 == x,
> # in integer arithmetic, for x <= 5.
> #
> # The "exponential" algorithm is a bit long at the low
> # end. We might consider stretching there. Or increasing
> # MIN.
>
> MIN=20
> if [ "$CURR" -lt "$MIN" ] ; then CURR="$MIN" ; fi
>
> # NOTE: 11/13 is approx the fourth root of 1/2:
> #       i.e. four steps are a doubling/halving
> #       of brightness (constant steps gave too
> #       coarse jumps in the low range)
>
> case $1 in
>   video/brightnessdown* )
>     NEW=$(( (11 * CURR) / 13 )) 
>     ;;
>   video/brightnessup* )
>     NEW=$(( (13 * CURR) / 11 )) 
>     ;;
>   * )
>     exit 0
>     ;;
> esac
>
> if [ "$NEW" -lt "$MIN" ] ; then NEW="$MIN" ; fi
> if [ "$NEW" -gt "$MAX" ] ; then NEW="$MAX" ; fi
> logger "[ACPI] brightness $CURR --> $NEW"
> echo "$NEW" > $BASE/brightness
> --- ---
>
> (The charm of using ACPI is that it works independently of X).
>
> To find which events to wait on, just run acpi_listen on a
> terminal and hit your dream's key.


Following your example, I aptitude-installed acpid and created
/etc/apt/events/briteup and /etc/acpi/actions/brite and filled them with the
stuff you reported; and then I did `chmod +x brite'...  Then?

Thanks,

Rodolfo