laptop battery charging control?

[David Chmelik]

Is there laptop battery charging control for FreeBSD UNIX? I have two
Lenovo ThinkPad X1 Yoga 20s (FR, UB) and read it's possible, but an
article I read was for older ThinkPads (maybe IBM) so those instructions
didn't work. I'd like to keep them plugged-in with battery to stop
charging at 70% and restart at 50%.

[Andreas Kempe]

I've been using the patch from
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=234403 that adds
this functionality to the acpi_ibm module. It gives you two sysctls,
dev.acpi_ibm.0.bat0_charge_stop and dev.acpi_ibm.0.bat0_charge_start
that can be set to you desired percentages to start and stop charging.

It works well on my X280, but I don't know if it applies on the X1 as
well.

[David Chmelik]

Looked at that report and found a script to set charge thresholds, but got
the following errors (not clear to me yet if I have to load some module/
driver).

root@microcosmos:~ # battery_ctrl.sh
acpi_call kernel modules not loaded.
loading acpi_call ...
kldload: can't load acpi_call: No such file or directory
acpi_call kernel modules failed to load.

[David Chmelik]

Loaded that then it said the below (so apparently not dev.acpi_ibm
anymore, but I don't know what replaces it after Lenovo took over from
IBM).

root@microcosmos:~/freebsd.sys/etc # battery_ctrl.sh 50 70
sysctl: unknown oid 'dev.acpi_ibm.0.%location'
[: Unknown: unexpected operator
start threshold was set to : 50
[: Unknown: unexpected operator
stop threshold was set to : 70

[Andreas Kempe]

acpi_ibm is not just for IBM ThinkPads, the historical name just stuck
around. Try kldload acpi_ibm and dev.acpi_ibm.0.%location should
become available.

[David Chmelik]

That works; thanks! Just wondering if I need to do these after reboot or
put in some /etc configuration file...

[Andreas Kempe]

On my X280, the computer remembers the setting as long as I don't
completely discharge the battery.