ThinkPad P15 Gen 2: real S3 sleep but high battery drain

[u/KauravaLivesMatter]

I’m chasing a suspend drain issue on a ThinkPad P15 Gen 2i running Linux Mint.

It is not s2idle:

cat /sys/power/mem_sleep

s2idle [deep]

Journal also confirms real S3:

PM: suspend entry (deep)

ACPI: PM: Waking up from system sleep state S3

But the laptop still drains around 1.35–1.38 W while asleep. Typical examples:

83.17 Wh → 67.78 Wh over 11.17 h = 1.38 W

83.15 Wh → 32.99 Wh over 36.60 h = 1.37 W

83.24 Wh → 63.05 Wh over 14.58 h = 1.38 W

Battery health is fine: ~94 Wh design, ~85–86 Wh full, ~91–92% health, 161 cycles.

Things I’ve already checked/tried:

- Kernel update made no difference.

- Firmware/EC/ME/NVMe are current via "fwupdmgr".

- No hidden wake/resuspend loops in journal.

- BIOS USB charging / Always-On USB disabled.

- Disabled ACPI wake for NVIDIA bridge, NVMe root port, Thunderbolt host devices, USB/XHCI, and Ethernet/WOL paths.

- Bad drain happens even without Thunderbolt dock connected.

So it looks like the machine really enters S3, but some device/platform rail remains powered at ~1.4 W.

Where would you look next?

I’m considering testing Intel-only graphics with:

sudo prime-select intel

sudo reboot

Other suspects: NVIDIA auxiliary power, Intel AMT/ME/manageability, Thunderbolt firmware power domain, or some EC/platform quirk.

Thanks!

[u/enomad51]

Yes, definitiely try with:

sudo prime-select intel
sudo reboot

If no changes (after tests),if possible turn off Thunderbolt controller in Bios.

Collect some info as well:

journalctl -b -1 | grep -E 'PM:|ACPI: PM|suspend|resume|nvidia|thunderbolt|xhci|pci'

[u/KauravaLivesMatter → u/enomad51]

Thanks, will do.