ALSA: hda - Don't initialize CORB/RIRB for single_cmd mode

So far, CORB/RIRB still remains even if the driver is switched to the
single_cmd mode.  The specification says that this should be disabled,
but I hoped this isn't the case; indeed most devices worked together with
CORB/RIRB.

However, Poulsbo (US15W) seems problematic with this setup, and it
requires to disable CORB/RIRB when single_cmd is used.

Now this patch disables CORB/RIRB initialization when the single_cmd
mode is used.  Also the unsolicited event is disabled because it can't
work without RIRB.
Reported-and-tested-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_intel.c

@@ -722,9 +722,10 @@ static unsigned int azx_rirb_get_response(struct hda_bus *bus,
 		   chip->last_cmd[addr]);
 	chip->single_cmd = 1;
 	bus->response_reset = 0;
-	/* re-initialize CORB/RIRB */
+	/* release CORB/RIRB */
 	azx_free_cmd_io(chip);
-	azx_init_cmd_io(chip);
+	/* disable unsolicited responses */
+	azx_writel(chip, GCTL, azx_readl(chip, GCTL) & ~ICH6_GCTL_UNSOL);
 	return -1;
 }
 
@@ -865,7 +866,9 @@ static int azx_reset(struct azx *chip)
 	}
 
 	/* Accept unsolicited responses */
-	azx_writel(chip, GCTL, azx_readl(chip, GCTL) | ICH6_GCTL_UNSOL);
+	if (!chip->single_cmd)
+		azx_writel(chip, GCTL, azx_readl(chip, GCTL) |
+			   ICH6_GCTL_UNSOL);
 
 	/* detect codecs */
 	if (!chip->codec_mask) {
@@ -980,6 +983,7 @@ static void azx_init_chip(struct azx *chip)
 	azx_int_enable(chip);
 
 	/* initialize the codec command I/O */
+	if (!chip->single_cmd)
 		azx_init_cmd_io(chip);
 
 	/* program the position buffer */