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;
}
--
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