Issues with vgaswitcheroo disappearing?

[dffx]

Can you bisect?

I've never done so before, and am not terrible familiar with the process. I did, however, do a little poking and prodding of my own and I found:



1. It seems to be an issue with xf86-video-ati/intel, which I had assumed

2. When using latest git builds of either, disabling the discrete card via vgaswitcheroo causes /sys/kernel/debug/vgaswitcheroo to disappear, meaning I can't re-enable it

3. When using the stable versions from the Arch Linux repos ( https://www.archlinux.org/packages/e...6-video-intel/ && https://www.archlinux.org/packages/e...f86-video-ati/ ) vgaswitcheroo/switch reports the discrete card being OFF. However, once I start X, /sys/kernel/debug/vgaswitcheroo disappears so I cannot re-start the discrete card

4. When using a recent git build of linux-next + stable intel/ati drivers I can start X successfully but the entire machine then crashes after about a minute with an error "unable to handle paging request", which was just dumped to stdout so I'll need to try to replicate that and capture the error. With this test I am *not* using vgaswitcheroo at all; I assume the crash occurs when the system tries to disable the discrete card



I'm still digging around with this to see what I can find. I'm *hoping* it's not bad hardware T__T

[agd5f]

Can you bisect?

[dffx]

You shouldn't need to mess with vgaswitcheroo in 3.13. The driver automatically powers down the card when not in use.

The trouble is though, when using 3.13, I'm getting the same behavior -- CPU locks, specifically -- as when I would `echo OFF > /sys/kernel/debug/vgaswitcheroo` , so I'm not sure if I'm doing something wrong or there's some other issue.

I'll try to see if I can get some of the error output.

[agd5f]

You shouldn't need to mess with vgaswitcheroo in 3.13. The driver automatically powers down the card when not in use.

[dffx]

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. 64bit Arch.

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, looks like CPU locks

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?