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.
thanks,
Takashi
--- diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index f09ff6c..9a0a29d 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -829,8 +829,9 @@ static void azx_update_rirb(struct azx *chip) smp_wmb(); chip->rirb.cmds[addr]--; } else - snd_printk(KERN_ERR SFX "spurious response %#x:%#x, " + snd_printk(KERN_ERR SFX "%s: spurious response %#x:%#x, " "last cmd=%#08x\n", + pci_name(chip->pci), res, res_ex, chip->last_cmd[addr]); }