[coreboot] [coreboot - Bug #427] x200: Two battery charging issues

[Akura Ryu]

Issue #427 has been updated by Akura Ryu.

Angel Pons wrote in #note-4:
> Hi,
>
> Yes, the EC should be reset by unplugging all power supplies, as it loses power. The RTC/CMOS battery shouldn't matter, but it would be a good idea to disconnect it as well if it's easy to do so.

Now battery threshold seems to work well when connecting adapter after system boot. But Issue 1 still exists.

Here I summarize when Issue 1 occurs:
- Connect to AC adapter when X200 is off.
- **Charging capacity reaches `stop_charge_thresh`.** KDE shows "battery is full" even though adapter has already disconnected (normally it should be "discharging").

----------------------------------------
Bug #427: x200: Two battery charging issues
https://ticket.coreboot.org/issues/427#change-1189

* Author: Akura Ryu
* Status: New
* Priority: High
* Category: board support
* Target version: master
* Start date: 2022-10-14
* Affected versions: master
* Needs backport to: master
* Affected hardware: ThinkPad X200
* Affected OS: Linux
----------------------------------------
I've flashed my ThinkPad X200 with coreboot. Currently it has trouble when charging.

## 1. Charge state mismatch
When I plug in my AC adapter, system always reports " **Not charging** ".

Here's the output from the `acpi` utility:
```
Battery 0: Not charging, 23%
Adapter 0: on-line
```

But weirdly, battery level is still increasing as the AC adapter is on-line.

What's more, it still reports "Not charging" when AC adapter is detached (normally it should be "Discharging").

## 2. Battery threshold doesn't seem to work.

Since tp_smapi is unusable without stock firmware, I use `tpacpi-bat` to configure battery threshold. My KDE battery indicator can recognize these thresholds.

```sh
sudo tpacpi-bat -s ST 1 88    # Start threshold
sudo tpacpi-bat -s SP 1 90    # Stop threshold
```

But no matter how I charge, battery will always be fully charged.

## Revision
- **OS**: Arch Linux with KDE
- **Coreboot revision**: 93781523a
- **Configuration**: See attachment

---Files--------------------------------
.config (18.8 KB)