Messages in this thread Patch in this message | | | Date | Tue, 09 Oct 2012 15:04:35 +0200 | From | Takashi Iwai <> | Subject | Re: [3.6-rc7] switcheroo race with Intel HDA... |
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At Tue, 9 Oct 2012 19:23:56 +0800, Daniel J Blueman wrote: > > On 9 October 2012 18:07, Takashi Iwai <tiwai@suse.de> wrote: > > 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?
Takashi
--- diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index f09ff6c..676c64d 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -2639,13 +2640,13 @@ static void azx_vs_set_state(struct pci_dev *pci, disabled ? "Disabling" : "Enabling", pci_name(chip->pci)); if (disabled) { + snd_hda_lock_devices(chip->bus); azx_suspend(&pci->dev); chip->disabled = true; - snd_hda_lock_devices(chip->bus); } else { - snd_hda_unlock_devices(chip->bus); chip->disabled = false; azx_resume(&pci->dev); + snd_hda_unlock_devices(chip->bus); } } }
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