ALSA: hda - Suppress CORBRP clear on Nvidia controller chips

The recent commit (ca460f86) changed the CORB RP reset procedure to
follow the specification with a couple of sanity checks.
Unfortunately, Nvidia controller chips seem not following this way,
and spew the warning messages like:
  snd_hda_intel 0000:00:10.1: CORB reset timeout#1, CORBRP = 0

This patch adds the workaround for such chips.  It just skips the new
reset procedure for the known broken chips.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_controller.c

@@ -1059,24 +1059,26 @@ static void azx_init_cmd_io(struct azx *chip)
 
 	/* reset the corb hw read pointer */
 	azx_writew(chip, CORBRP, ICH6_CORBRP_RST);
-	for (timeout = 1000; timeout > 0; timeout--) {
-		if ((azx_readw(chip, CORBRP) & ICH6_CORBRP_RST) == ICH6_CORBRP_RST)
-			break;
-		udelay(1);
-	}
-	if (timeout <= 0)
-		dev_err(chip->card->dev, "CORB reset timeout#1, CORBRP = %d\n",
-			azx_readw(chip, CORBRP));
+	if (!(chip->driver_caps & AZX_DCAPS_CORBRP_SELF_CLEAR)) {
+		for (timeout = 1000; timeout > 0; timeout--) {
+			if ((azx_readw(chip, CORBRP) & ICH6_CORBRP_RST) == ICH6_CORBRP_RST)
+				break;
+			udelay(1);
+		}
+		if (timeout <= 0)
+			dev_err(chip->card->dev, "CORB reset timeout#1, CORBRP = %d\n",
+				azx_readw(chip, CORBRP));
 
-	azx_writew(chip, CORBRP, 0);
-	for (timeout = 1000; timeout > 0; timeout--) {
-		if (azx_readw(chip, CORBRP) == 0)
-			break;
-		udelay(1);
+		azx_writew(chip, CORBRP, 0);
+		for (timeout = 1000; timeout > 0; timeout--) {
+			if (azx_readw(chip, CORBRP) == 0)
+				break;
+			udelay(1);
+		}
+		if (timeout <= 0)
+			dev_err(chip->card->dev, "CORB reset timeout#2, CORBRP = %d\n",
+				azx_readw(chip, CORBRP));
 	}
-	if (timeout <= 0)
-		dev_err(chip->card->dev, "CORB reset timeout#2, CORBRP = %d\n",
-			azx_readw(chip, CORBRP));
 
 	/* enable corb dma */
 	azx_writeb(chip, CORBCTL, ICH6_CORBCTL_RUN);

sound/pci/hda/hda_intel.c

@@ -249,7 +249,8 @@ enum {
 /* quirks for Nvidia */
 #define AZX_DCAPS_PRESET_NVIDIA \
 	(AZX_DCAPS_NVIDIA_SNOOP | AZX_DCAPS_RIRB_DELAY | AZX_DCAPS_NO_MSI |\
-	 AZX_DCAPS_ALIGN_BUFSIZE | AZX_DCAPS_NO_64BIT)
+	 AZX_DCAPS_ALIGN_BUFSIZE | AZX_DCAPS_NO_64BIT |\
+	 AZX_DCAPS_CORBRP_SELF_CLEAR)
 
 #define AZX_DCAPS_PRESET_CTHDA \
 	(AZX_DCAPS_NO_MSI | AZX_DCAPS_POSFIX_LPIB | AZX_DCAPS_4K_BDLE_BOUNDARY)

sound/pci/hda/hda_priv.h

@@ -189,6 +189,7 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
 #define AZX_DCAPS_COUNT_LPIB_DELAY  (1 << 25)	/* Take LPIB as delay */
 #define AZX_DCAPS_PM_RUNTIME	(1 << 26)	/* runtime PM support */
 #define AZX_DCAPS_I915_POWERWELL (1 << 27)	/* HSW i915 powerwell support */
+#define AZX_DCAPS_CORBRP_SELF_CLEAR (1 << 28)	/* CORBRP clears itself after reset */
 
 /* position fix mode */
 enum {