Arch Linux

Forthwith

Member

Registered: 2012-01-10

Posts: 3

Thinkpad T400 using 2x more power on resume

I have a Thinkpad T400 running the x86_64 version of arch. The first time it runs (before a suspend/resume) it uses about 9-10W on idle. After a resume, it uses about 16-20W.

It has hybrid graphics, but I think I have vga_switcheroo correctly enabled - I've followed all the directions in the wiki and /sys/kernel/debug/vgaswitcheroo/switch shows Discrete as Off.

I've installed and minimally configured TLP so that all Tunables in powertop2 are "Good"

I don't think I'm running a power manager (where did gnome-power-manager go after Gnome 3?) but upowerd is running.

I have no idea what is happening. Would appreciate any and all help.

Forthwith

Member

Registered: 2012-01-10

Posts: 3

Re: Thinkpad T400 using 2x more power on resume

Hmm, weird.

Before any resumes, if I do

echo ON > /sys/kernel/debug/vgaswitcheroo/switch
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch

radeon will be turned on and off properly.

But after a resume, if I try the same thing, I get

[drm:r600_ring_test] *ERROR* radeon: ring test failed (scratch(0x8504)=0xFFFFFF)
[drm:r600_resume] r600 startup failed on resume

On the other hand, radeon will still switch off and power usage will go down to it normal values.

For now, I just turn radeon on and off using the code above in a resume hook in pm-utils but this seems like a workaround for something there's a proper solution for. Somehow the ATI card is being turned on again on resume and vgaswitcheroo isn't preventing that. Also it seems that after resume vgaswitcheroo isn't even trying to resume the right card: r600 seems to refer to a HD6xxx series card and I have a 3470 or something like that.