At Fri, 12 Oct 2012 23:08:14 +0800, Daniel J Blueman wrote:

On 10 October 2012 20:34, Takashi Iwai tiwai@suse.de wrote:

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At Tue, 9 Oct 2012 22:26:40 +0800, Daniel J Blueman wrote:

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On 9 October 2012 21:04, Takashi Iwai tiwai@suse.de wrote:

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At Tue, 9 Oct 2012 19:23:56 +0800, Daniel J Blueman wrote:

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On 9 October 2012 18:07, Takashi Iwai tiwai@suse.de wrote:

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At Tue, 09 Oct 2012 12:04:08 +0200, Takashi Iwai wrote: > At Tue, 9 Oct 2012 00:34:09 +0800, > Daniel J Blueman wrote: > > On 8 October 2012 20:58, Takashi Iwai tiwai@suse.de wrote: > > > At Tue, 25 Sep 2012 13:20:05 +0800, > > > Daniel J Blueman wrote: > > >> On my Macbook with a discrete Nvidia GPU, there is a race between > > >> selecting the integrated GPU and putting the discrete GPU into D3 [1], > > >> reliably causing a kernel oops [2]. > > >> > > >> Introducing a delay of ~1s between the calls prevents this. When the > > >> second 'OFF' write path executes, it looks like struct azx at > > >> card->private_data hasn't yet been allocated yet [3], so there is > > >> likely some locking missing. > > > > > > It's rather pci_get_drvdata() returning NULL (i.e. card is NULL, thus > > > card->private_data causes Oops). Could you check the patch like below > > > and see whether you get a kernel warning (but no Oops) or the problem > > > gets fixed by shifting the assignment of pci drvdata? > > [...] > > > > Good patching. Calling pci_set_drvdata later prevents the oops in HDA, > > though we see unexpected 0x0 responses in the response ring buffer > > [1], which we don't see when there's a >~1.5s delay between IGD and > > OFF. > > If the previous patch fixed, it means that the switching occurred > during the device was being probed. Maybe a better approach to > register the VGA switcheroo after the proper initialization. > > The patch below is a revised one. Please give it a try.

Also, it's not clear which card spews the spurious response. Apply the patch below in addition.

[...]

hda-intel: 0000:01:00.1: spurious response 0x0:0x0, last cmd=0x1f0004 $ lspci -s :1:0.1 01:00.1 Audio device: NVIDIA Corporation Device 0e1b (rev ff)

It's the NVIDIA device which presumably hasn't completed it's transition to D3 at the time the OFF is executed.

OK, then could you try the patch below on the top of previous two patches?

The first IGD switcheroo command fails to switch to the integrated GPU:

# cat /sys/kernel/debug/vgaswitcheroo/switch 0:DIS:+:Pwr:0000:01:00.0 1:IGD: :Pwr:0000:00:02.0 2:DIS-Audio: :Pwr:0000:01:00.1 # echo IGD >/sys/kernel/debug/vgaswitcheroo/switch vga_switcheroo: client 1 refused switch

I also instrumented snd_hda_lock_devices, but none of the failure paths are being taken, which would leave inconsistent state, as the return value isn't checked.

Hm, right, the return value of snd_hda_lock_devices() isn't checked, but I don't understand how this results like above. Basically switching is protected by mutex in vga_switcheroo.c, so the whole operation in the client side should be serialized.

In anyway, try the patch below cleanly, and see the spurious message error coming up at which timing.

[...]

The patch _does_ address the issue. A recent update to my Macbook firmware misleadingly broke i915 switching, but since I can reproduce the oops without the IGD switching completing with the stock kernel, and consistently can't without [1], the patch is good.

Tested-by: Daniel J Blueman daniel@quora.org

OK, then I'm going to apply the patch to 3.7 tree (with Cc to stable).

thanks,

Takashi

Thanks Takashi! Daniel

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snd_hda_intel 0000:00:1b.0: enabling device (0000 -> 0002) snd_hda_intel 0000:00:1b.0: irq 54 for MSI/MSI-X XXX 0000:00:1b.0: azx_codec_create entered vga_switcheroo: enabled XXX 0000:00:1b.0: azx_codec_create done input: HDA Intel PCH Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input9 snd_hda_intel 0000:01:00.1: enabling device (0000 -> 0002) hda_intel: Disabling MSI hda-intel: 0000:01:00.1: Handle VGA-switcheroo audio client XXX 0000:01:00.1: azx_codec_create entered XXX 0000:01:00.1: azx_codec_create done input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input12 input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input13 input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input14 vga_switcheroo: client 1 refused switch i915: switched off -- Daniel J Blueman