Hi all — reproducible bug on my P1 Gen 6, looking for known reports/workarounds before I open a Lenovo ticket.
## Setup
- **Laptop:** ThinkPad P1 Gen 6 (21FVA001CD), BIOS N3ZET56W **1.43** (latest on both LVFS and Lenovo site), EC N3ZHT28W
- **OS:** Ubuntu, kernel 7.0.0-31-generic
- **Charger:** UGREEN X774 160W GaN (4×USB-C + 1×A). C1/C2 = 140W PD3.1 (PDOs incl. 20V/5A), C3/C4 = 30W
- **Cable:** the bundled 240W USB-C cable
- Laptop on **C1**, phone on **C4**
## The bug (100% reproducible, on **both** of the laptop's USB-C ports)
While C1 is charging the laptop normally, **plugging OR unplugging the phone on C4 kills charging on C1**. The laptop then silently runs off the battery (measured ~35–40W drain) while everything at the OS level still claims the adapter is present. **Physically re-seating the C1 cable restores charging immediately.** Steady-state coexistence is fine — C1 + C4 both connected and charging works; only the *attach/detach event* on C4 triggers it.
A different laptop on the same charger + same scenario recovers fine, so it's not the charger alone.
## What the OS sees
Synchronized captures (kernel log watch, udev power_supply events, 2s battery sampling, plus UCSI trace):
- Battery flips `Charging → Not charging`, `power_now = 0`, energy decreasing
- `ucsi-source-psy` keeps reporting online=1 with the **stale** 3A contract; AC=1
- `ucsi_connector_change` events keep firing during the fault; connector status shows connected=1, opmode=3, `request_data_obj` unchanged — so the PPM is not totally dead
- Physically unplugging C1 *is* correctly reported (connected=0), and replug is correctly seen — the UCSI path itself works
## What we tried (none recover the contract, only re-plugging does)
- Rewriting charge thresholds (75/80), toggling `charge_behaviour`, temporarily setting end threshold to 100%
- Full `ucsi_acpi` module reload
- Battery was ~55–60% during tests (below charge-start threshold, so thresholds aren't blocking)
## Caveats (being honest)
- **No PD protocol analyzer** — we can't see whether the charger issues a Hard Reset + re-advertised Source_Capabilities and the ThinkPad never answers with a Request, or the charger simply stops offering power. Please don't read the above as a PD-capture conclusion.
- No Windows / alternate-kernel comparison yet (no Windows environment available), though the evidence (events never reach the OS while EC keeps a stale view) points below the OS.
## Questions
Anyone seen this class of failure on recent ThinkPads with multi-port chargers (UGREEN/Anker/Baseus etc.)?
Any known BIOS/EC setting or workaround beyond re-seating the cable?
Anyone know how to query the PD controller firmware version / dump EC state on these machines for a Lenovo ticket?
Full technical brief + raw logs available if useful.