Bug 1047276 - vgaswitcheroo not working on kernel 3.12
Summary: vgaswitcheroo not working on kernel 3.12
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 20
Hardware: x86_64
OS: Linux
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2013-12-30 09:50 UTC by lapseofreason0
Modified: 2014-01-19 08:28 UTC (History)
8 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2014-01-19 08:28:41 UTC
Type: Bug

Attachments (Terms of Use)
patch from https://lkml.org/lkml/2013/12/31/162 changed for kernel 3.12.6 (6.57 KB, patch)
2014-01-05 21:56 UTC, lapseofreason0
no flags Details | Diff

System ID Private Priority Status Summary Last Updated
FreeDesktop.org 70687 0 None None None Never

Description lapseofreason0 2013-12-30 09:50:21 UTC
vgaswitcheroo is not working on kernel 3.12 because /sys/kernel/debug/vgaswitcheroo is missing. As a consequence, it is not possible to control the discrete graphics card.

This seems to be due to a driver conflict between shpchp and another pci acpi hotplug driver (which is compiled into the kernel by default). Recompiling the kernel with 
fixes the issue (see comment 13 in linked bug report).

Affected packages: kernel-3.12.5-302.fc20.x86_64 and earlier 3.12 kernels

Was working fine on 2.11 kernel (Fedora 19).

Comment 1 Michele Baldessari 2014-01-01 09:13:45 UTC
At least this patch seems to be needed. Although I am not 100% sure it will be enough:

Can you give the patch a try and report back?

Comment 2 lapseofreason0 2014-01-02 13:08:26 UTC
I'm away for a couple of days, I'll test the patch when I'm back. Thanks!

Comment 3 lapseofreason0 2014-01-05 21:56:36 UTC
Created attachment 845836 [details]
patch from https://lkml.org/lkml/2013/12/31/162 changed for kernel 3.12.6

I patched kernel 3.12.6 with the patch you provided and /sys/kernel/debug/vgaswitcheroo is now present and works as expected.

I had to slightly change the patch so it would apply to 3.12.6 so I attached the new patch.

Comment 4 Michele Baldessari 2014-01-05 22:16:56 UTC
Perfect. Thanks for testing. I'll let the kernel team see if it makes
sense picking it up before it trickles down via linux-stable.

Comment 5 Josh Boyer 2014-01-06 18:56:36 UTC
Greg is working on importing patches for 3.12.7 right now.  Let's wait for a couple days and see if he grabs this one and includes it.  If not, we can apply it ourselves.

Comment 6 Josh Boyer 2014-01-12 14:19:38 UTC
3.12.7 is in updates-testing now.

Comment 7 lapseofreason0 2014-01-19 08:28:41 UTC
Works with kernel 3.12.7 which is now available through updates.

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