Huawei Matebook X Pro 2020 - battery charge threshold - end seems active, start seems inactive about huawei-wmi

[Helium314]

I can semi-confirm the issue.
My device is a Matebook X Pro 2018, not 2020. Otherwise it's the same, also using Ubuntu 20.04.
Both charge thresholds used to work previously, but now the lower one doesn't. I only noticed it a month ago, now sure when it started.
Don't have Windows for comparing behavior.

[jerabaul29]

dmidecode.txt
dmesg.txt
acpidump.txt

[aymanbagabas]

Is this behavior the same in Windows?

[jerabaul29]

What do you mean @aymanbagabas ? :)

[jerabaul29]

I have wiped off windows, no way to do any windows Vs Linux tests for my part unfortunately if this is what you mean. But I am pretty sure that this is not the expected behaviour. On my ThinkPads with tlp enabled and similar threshold, the effect of start threshold is that charging starts only when battery level falls below the threshold - to avoid super many small charging around the top threshold).

[aymanbagabas]

ThinkPads != Matebooks, different vendors have different specifications. If this is happening with Huawei-WMI then I'm pretty certain Windows will give you the same behavior since both PC Manager and this driver use the same underlying interface.

Closing until you verify or someone with the same device verifies the issue. Sorry

[aymanbagabas]

@Helium314 could you try the wq branch and test it from there?

[Helium314]

Battery at 83%, thresholds at 60 and 88.
Started charging as soon as I plugged in.
Stopped when setting upper limit to 83, but started again after setting to 84.

After plugging/unplugging and changing thresholds a few times it started working properly (until reboot). Not sure what exactly caused this... will try again tomorrow.

[Helium314]

Current behavior, checked using /sys/class/power_supply/BAT0/power_now and /sys/class/power_supply/BAT0/status

battery	start threshold	end theshold	charging
69	60	80	yes
69	60	70	no
69	60	65	discharging
71	70	70	yes
71	70	71	discharging
72	71	73	no

charging result never changed after unplugging and plugging.
The discharing despite being plugged is something that definitely didn't happen before...

Yesterday I was able to get it working correctly (i.e. same behavior as described in #35) one more time after a lot of plugging, unplugging and threshold changing, today I wasn't.

[Helium314]

I did not manage to reliably reproduce the switch to a working-as-usual state. Only notable thing is that when the switch works, the command (e..g echo 70 > /sys/class/power_supply/BAT0/charge_control_end_threshold) takes about a second to finish, as opposed to the normal immediate execution.

Anyway, the root cause appears to be a BIOS update to 1.36 I did in summer (before removing Windows 10). On BIOS 1.29 everything works as it used to.

[jerabaul29]

Should this issue be re-open since we are several who can confirm the issue and the bug seems "reproducible"? :) . Then of course it is a question if this should be also forwarded to Huawei (if there is an issue with their BIOS? or is it some other organisation that "produces" the BIOS? a bit of a n00b there :) )?

[Helium314]

BIOS is coming from Huawei, and I just saw there is a newer version 1.37 for Matebook X Pro 2018, maybe it's a related bugfix.
If new BIOS version changes the intended behavior, then issue could maybe be re-opened, but if it's a bug it has nothing to do with the Huawei-WMI here.

[jerabaul29]

:) .