[ALSA] hda-intel - Add black/whitelist for position_fix option

Some devices are known to require position_fix=1 or 2 to make the
driver working correctly.  Otherwise the sound gets weird effects,
such as stutters.
Now a black/whitelist is introduced to indicate the position_fix
value explicitly for such misbehaving hardwares.  As a first example,
Dell D820 is listed there.  More will come later likely...

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 27 insertions, 1 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 83d1ba7f33a0..b9a8e238b0a8 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1503,6 +1503,31 @@ static int azx_dev_free(struct snd_device *device)
 }
 
 /*
+ * white/black-listing for position_fix
+ */
+static const struct snd_pci_quirk position_fix_list[] __devinitdata = {
+        SND_PCI_QUIRK(0x1028, 0x01cc, "Dell D820", POS_FIX_NONE),
+        {}
+};
+
+static int __devinit check_position_fix(struct azx *chip, int fix)
+{
+        const struct snd_pci_quirk *q;
+
+        if (fix == POS_FIX_AUTO) {
+                q = snd_pci_quirk_lookup(chip->pci, position_fix_list);
+                if (q) {
+                        snd_printdd(KERN_INFO
+                                    "hda_intel: position_fix set to %d "
+                                    "for device %04x:%04x\n",
+                                    q->value, q->subvendor, q->subdevice);
+                        return q->value;
+                }
+        }
+        return fix;
+}
+
+/*
  * constructor
  */
 static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
@@ -1536,7 +1561,8 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
         chip->driver_type = driver_type;
         chip->msi = enable_msi;
 
-        chip->position_fix = position_fix;
+        chip->position_fix = check_position_fix(chip, position_fix);
+
         chip->single_cmd = single_cmd;
 
 #if BITS_PER_LONG != 64