[PATCH] ALSA: hda - Add position_fix=4 (COMBO) option

[PATCH] ALSA: hda - Add position_fix=4 (COMBO) option

[Takashi Iwai]

This patch adds a new position_fix option value, 4, as a combo mode
to use LPIB for playbacks and POSBUF for captures.  It's the way
recommended by Intel hardware guys.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

Seth, this is the patch to add the mode you mentioned.
It'll be queued for 3.4 kernel.  This mode isn't chosen as default yet,
but if this is confirmed to work more reliably on Intel controllers,
we can set these as default for them.

 Documentation/sound/alsa/ALSA-Configuration.txt |    8 +++++++-
 Documentation/sound/alsa/HD-Audio.txt           |    7 ++++++-
 sound/pci/hda/hda_intel.c                       |   10 +++++++++-
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 936699e..9af64c5 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -860,7 +860,8 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 
     [Multiple options for each card instance]
     model	- force the model name
-    position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF)
+    position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF,
+    		   3 = VIACOMBO, 4 = COMBO)
     probe_mask  - Bitmask to probe codecs (default = -1, meaning all slots)
     		  When the bit 8 (0x100) is set, the lower 8 bits are used
 		  as the "fixed" codec slots; i.e. the driver probes the
@@ -925,6 +926,11 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 	    (Usually SD_LPIB register is more accurate than the
 	    position buffer.)
 
+	    position_fix=3 is specific to VIA devices.  The position
+	    of the capture stream is checked from both LPIB and POSBUF
+	    values.  position_fix=4 is a combination mode, using LPIB
+	    for playback and POSBUF for capture.
+
     NB: If you get many "azx_get_response timeout" messages at
     loading, it's likely a problem of interrupts (e.g. ACPI irq
     routing).  Try to boot with options like "pci=noacpi".  Also, you
diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt
index 91fee3b..7813c06 100644
--- a/Documentation/sound/alsa/HD-Audio.txt
+++ b/Documentation/sound/alsa/HD-Audio.txt
@@ -59,7 +59,12 @@ a case, you can change the default method via `position_fix` option.
 `position_fix=1` means to use LPIB method explicitly.
 `position_fix=2` means to use the position-buffer.
 `position_fix=3` means to use a combination of both methods, needed
-for some VIA and ATI controllers.  0 is the default value for all other
+for some VIA controllers.  The capture stream position is corrected
+by comparing both LPIB and position-buffer values.
+`position_fix=4` is another combination available for all controllers,
+and uses LPIB for the playback and the position-buffer for the capture
+streams.
+0 is the default value for all other
 controllers, the automatic check and fallback to LPIB as described in
 the above.  If you get a problem of repeated sounds, this option might
 help.
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index e354c16..6e958bf 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -84,7 +84,7 @@ module_param_array(model, charp, NULL, 0444);
 MODULE_PARM_DESC(model, "Use the given board model.");
 module_param_array(position_fix, int, NULL, 0444);
 MODULE_PARM_DESC(position_fix, "DMA pointer read method."
-		 "(0 = auto, 1 = LPIB, 2 = POSBUF, 3 = VIACOMBO).");
+		 "(0 = auto, 1 = LPIB, 2 = POSBUF, 3 = VIACOMBO, 4 = COMBO).");
 module_param_array(bdl_pos_adj, int, NULL, 0644);
 MODULE_PARM_DESC(bdl_pos_adj, "BDL position adjustment offset.");
 module_param_array(probe_mask, int, NULL, 0444);
@@ -330,6 +330,7 @@ enum {
 	POS_FIX_LPIB,
 	POS_FIX_POSBUF,
 	POS_FIX_VIACOMBO,
+	POS_FIX_COMBO,
 };
 
 /* Defines for ATI HD Audio support in SB450 south bridge */
@@ -2520,6 +2521,7 @@ static int __devinit check_position_fix(struct azx *chip, int fix)
 	case POS_FIX_LPIB:
 	case POS_FIX_POSBUF:
 	case POS_FIX_VIACOMBO:
+	case POS_FIX_COMBO:
 		return fix;
 	}
 
@@ -2699,6 +2701,12 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 
 	chip->position_fix[0] = chip->position_fix[1] =
 		check_position_fix(chip, position_fix[dev]);
+	/* combo mode uses LPIB for playback */
+	if (chip->position_fix[0] == POS_FIX_COMBO) {
+		chip->position_fix[0] = POS_FIX_LPIB;
+		chip->position_fix[1] = POS_FIX_AUTO;
+	}
+
 	check_probe_mask(chip, dev);
 
 	chip->single_cmd = single_cmd;
-- 
1.7.9

Re: [PATCH] ALSA: hda - Add position_fix=4 (COMBO) option

[David Henningsson]

On 02/28/2012 12:37 PM, Takashi Iwai wrote:
> This patch adds a new position_fix option value, 4, as a combo mode
> to use LPIB for playbacks and POSBUF for captures.  It's the way
> recommended by Intel hardware guys.

Interesting. More specifically, for what chips were this mode 
recommended? There were none added with the patch.

-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic

Re: [PATCH] ALSA: hda - Add position_fix=4 (COMBO) option

[Takashi Iwai]

At Tue, 28 Feb 2012 19:02:04 +0100,
David Henningsson wrote:
> 
> On 02/28/2012 12:37 PM, Takashi Iwai wrote:
> > This patch adds a new position_fix option value, 4, as a combo mode
> > to use LPIB for playbacks and POSBUF for captures.  It's the way
> > recommended by Intel hardware guys.
> 
> Interesting. More specifically, for what chips were this mode 
> recommended? There were none added with the patch.

I forward this question to Seth.

The patch didn't enable this mode as default simply because it wasn't
tested throughly, and I also don't know which should be set.
If we get more information from Intel h/w guys, and after confirming
it actually works (doesn't regress, at least), we can change the
default...


thanks,

Takashi