Arch Linux

snowblind

Member

Registered: 2013-07-18

Posts: 39

vgaswitcheroo and disabling discrete video card

I have a hybrid laptop -- Intel Ivybridge + AMD 7970M -- and I've been using the latest open source driver stack, keeping up to date with the latest developments.

With 3.13 we're going to have runtime power management, which will be fantastic for battery life. However, I'm running into an issue: whenever I disable my discrete card using `echo OFF > /sys/kernel/debug/vgaswitcheroo/switch` one of two things happens:

    a) I get a ton of error messages in dmesg, cpu locks it looks like

    b) I get no errors, but /sys/kernel/debug/vgaswitcheroo disappears

I noticed this when testing some of the 3.13 changes, that my computer would mostly jus crash with CPU lock errors. I thought it was just an issue with 3.13, but going back to 3.12 I tried manually disabling the discrete card and, while X was running, my system would lockup, or, if X was *not* running, the vgaswitcheroo directory would vanish.

Has anyone run into this issue before, or maybe know a way of fixing it?

Thanks!

Ras

Member

From: Giran Castle Town

Registered: 2013-11-19

Posts: 2

Re: vgaswitcheroo and disabling discrete video card

Same problem here

3.12.0-1-ARCH
xf86-video-ati 1:7.2.0-1
xf86-video-intel 2.21.15-1

sano

Member

Registered: 2012-02-11

Posts: 114

Re: vgaswitcheroo and disabling discrete video card

I am not sure if simply echoing "OFF" is the right way to do this:

sudo cat /sys/kernel/debug/vgaswitcheroo/switch
0:IGD:+:Pwr:0000:00:02.0
1:DIS: :DynOff:0000:01:00.0

I have a Sandybridge - NV GT540M hybrid, so maybe this doesn't cover your cases.
But there were a lot of changes in kernel 3.12 regarding hybrid laptops, both for ATI/AMD and nVidia, so many instructions you find in the wiki and elsewhere could be outdated.

ichfarbstift

Member

Registered: 2011-11-22

Posts: 14

Re: vgaswitcheroo and disabling discrete video card

It seems to be a bug with 3.12, that will be fixed by rc2.
I think right now in Core there is rc1, but I am not sure how to check that.

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,211

Re: vgaswitcheroo and disabling discrete video card

according to the last comments on that bug, it was gone with rc2, but came back with 3.12 .
we're now on 3.12, so if a fix is found it will be in 3.12.1 or later versions

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky

Ras

Member

From: Giran Castle Town

Registered: 2013-11-19

Posts: 2

Re: vgaswitcheroo and disabling discrete video card

vgaswitcheroo runs perfect again with the 3.12.7-1-ARCH
I'm glad they fixed this, i couldn't turn my laptop to sleep for months