[ALSA] Add position_fix module option

Documentation,HDA Intel driver
Added position_fix module option to HDA-intel driver for fixing up
the DMA position (possibly hardware-) bugs.

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

1 files changed, 9 insertions, 0 deletions

diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index c69581ca2a34..ef07506e583c 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -618,6 +618,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
     Module for Intel HD Audio (ICH6, ICH6M, ICH7)
 
     model       - force the model name
+    position_fix - Fix DMA pointer (0 = FIFO size, 1 = none, 2 = POSBUF)
 
     Module supports up to 8 cards.
 
@@ -643,6 +644,14 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
           full_dig      6-jack in back, 2-jack in front, SPDIF I/O
           allout        5-jack in back, 2-jack in front, SPDIF out
 
+    Note 2: If you get click noises on output, try the module option
+            position_fix=1 or 2.  position_fix=1 will use the SD_LPIB
+            register value without FIFO size correction as the current
+            DMA pointer.  position_fix=2 will make the driver to use
+            the position buffer instead of reading SD_LPIB register.
+            (Usually SD_LPLIB register is more accurate than the
+            position buffer.)
+
   Module snd-hdsp
   ---------------