releases/3.6.2/alsa-hda-use-lpib-for-delay-estimation.patch

From 90accc58a6946e7245993da6079f88d8c29cb731 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Fri, 21 Sep 2012 18:39:06 -0500
Subject: ALSA: hda - use LPIB for delay estimation

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

commit 90accc58a6946e7245993da6079f88d8c29cb731 upstream.

DMA Position in Buffer (DPIB) should be used for
ring buffer management, while LPIB register provides
information on the number of samples transfered on
the link. The difference between the two pieces of
information corresponds to hardware/DMA buffering.

This patch reports this difference in runtime->delay, and
removes the use of the COMBO mode on recent Intel hardware.

Credits to Takashi Iwai for an initial patch.

[rebased to for-next branch and replaced snd_printk() with
 snd_printdd() by tiwai]

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/pci/hda/hda_intel.c |   36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -538,6 +538,7 @@ enum {
 #define AZX_DCAPS_ALIGN_BUFSIZE	(1 << 22)	/* buffer size alignment */
 #define AZX_DCAPS_4K_BDLE_BOUNDARY (1 << 23)	/* BDLE in 4k boundary */
 #define AZX_DCAPS_POSFIX_COMBO  (1 << 24)	/* Use COMBO as default */
+#define AZX_DCAPS_COUNT_LPIB_DELAY  (1 << 25)	/* Take LPIB as delay */
 
 /* quirks for ATI SB / AMD Hudson */
 #define AZX_DCAPS_PRESET_ATI_SB \
@@ -2120,6 +2121,27 @@ static unsigned int azx_get_position(str
 
 	if (pos >= azx_dev->bufsize)
 		pos = 0;
+
+	/* calculate runtime delay from LPIB */
+	if (azx_dev->substream->runtime &&
+	    chip->position_fix[stream] == POS_FIX_POSBUF &&
+	    (chip->driver_caps & AZX_DCAPS_COUNT_LPIB_DELAY)) {
+		unsigned int lpib_pos = azx_sd_readl(azx_dev, SD_LPIB);
+		int delay;
+		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+			delay = pos - lpib_pos;
+		else
+			delay = lpib_pos - pos;
+		if (delay < 0)
+			delay += azx_dev->bufsize;
+		if (delay >= azx_dev->period_bytes) {
+			snd_printdd("delay %d > period_bytes %d\n",
+				delay, azx_dev->period_bytes);
+			delay = 0; /* something is wrong */
+		}
+		azx_dev->substream->runtime->delay =
+			bytes_to_frames(azx_dev->substream->runtime, delay);
+	}
 	return pos;
 }
 
@@ -3260,7 +3282,7 @@ static DEFINE_PCI_DEVICE_TABLE(azx_ids)
 	/* CPT */
 	{ PCI_DEVICE(0x8086, 0x1c20),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* PBG */
 	{ PCI_DEVICE(0x8086, 0x1d20),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
@@ -3268,26 +3290,26 @@ static DEFINE_PCI_DEVICE_TABLE(azx_ids)
 	/* Panther Point */
 	{ PCI_DEVICE(0x8086, 0x1e20),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* Lynx Point */
 	{ PCI_DEVICE(0x8086, 0x8c20),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* Lynx Point-LP */
 	{ PCI_DEVICE(0x8086, 0x9c20),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* Lynx Point-LP */
 	{ PCI_DEVICE(0x8086, 0x9c21),
 	  .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* Haswell */
 	{ PCI_DEVICE(0x8086, 0x0c0c),
 	  .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	{ PCI_DEVICE(0x8086, 0x0d0c),
 	  .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_SCH_SNOOP |
-	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_POSFIX_COMBO },
+	  AZX_DCAPS_BUFSIZE | AZX_DCAPS_COUNT_LPIB_DELAY },
 	/* SCH */
 	{ PCI_DEVICE(0x8086, 0x811b),
 	  .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_SCH_SNOOP |