https://bugs.freedesktop.org/show_bug.cgi?id=100270

--- Comment #6 from Alex Deucher alexdeucher@gmail.com --- (In reply to brett.hassall from comment #5)

(In reply to Emil Velikov from comment #2)

...

If your bisection has gone right, you're looking at either c39b487f195b93235ee76384427467786f7bf29f (if you're running amdgpu) or b817634276f7f68c9d1d6d4a27117ff3c2f16956 (if you're on radeon).

lspci should tell you which one, and you should be able to revert either one on top of 4.8.5. Once you confirm the commit causing the issue, please change the component accordingly and CC the author - Alex Deucher.

Following the "git checkout tags/v4.8-rc3 -b bug" I reverted b817634276f7f68c9d1d6d4a27117ff3c2f16956. Power usage dropped by approx 4.5W (measured after login once system had settled, wifi not connected).

So apparently your system claims to support pcie pm (d3cold), but either doesn't or it's disabled for some reason.