[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>

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 83d1ba7f33a04cda257ce33124bac20615cb6591..b9a8e238b0a882bdc58071f43652294f939b73e8 100644 (file)
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1502,6 +1502,31 @@ static int azx_dev_free(struct snd_device *device)
        return azx_free(device->device_data);
 }
 
+/*
+ * 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
  */
@@ -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