Hi Daniel,
sorry for the late reply. I'm just back from vacation.
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?
thanks,
Takashi
--- diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index f09ff6c..152f9e1 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -2609,9 +2609,15 @@ static void azx_vs_set_state(struct pci_dev *pci, enum vga_switcheroo_state state) { struct snd_card *card = pci_get_drvdata(pci); - struct azx *chip = card->private_data; + struct azx *chip; bool disabled;
+ if (WARN_ON(!card)) + return; + + chip = card->private_data; + if (WARN_ON(!chip)) + return; if (chip->init_failed) return;
@@ -3314,6 +3320,7 @@ static int __devinit azx_probe(struct pci_dev *pci, }
snd_card_set_dev(card, &pci->dev); + pci_set_drvdata(pci, card);
err = azx_create(card, pci, dev, pci_id->driver_data, &chip); if (err < 0) @@ -3340,8 +3347,6 @@ static int __devinit azx_probe(struct pci_dev *pci, goto out_free; }
- pci_set_drvdata(pci, card); - if (pci_dev_run_wake(pci)) pm_runtime_put_noidle(&pci->dev);
@@ -3350,6 +3355,7 @@ static int __devinit azx_probe(struct pci_dev *pci,
out_free: snd_card_free(card); + pci_set_drvdata(pci, NULL); return err; }