commit 8bea869c5e56234990e6bad92a543437115bfc18
author Jaroslav Kysela <perex@perex.cz> Mon Apr 27 09:44:40 2009 +0200
committer Takashi Iwai <tiwai@suse.de> Fri May 29 11:47:33 2009 +0200
tree 7d0a5c4eeeeb69623066eccb363f35e0f2e3fda6
parent e93721a70263afefbac781f575bfe851c6f95d84

ALSA: PCM midlevel: improve fifo_size handling

Move the fifo_size assignment to hw->ioctl callback to allow lowlevel
drivers overwrite the default behaviour.

fifo_size is in frames not bytes as specified in asound.h and alsa-lib's
documentation, but most hardware have fixed byte based FIFOs. Introduce
internal SNDRV_PCM_INFO_FIFO_IN_FRAMES.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm_native.c

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 45dc53f..84da3ba 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -312,9 +312,18 @@
 
 	hw = &substream->runtime->hw;
 	if (!params->info)
-		params->info = hw->info;
-	if (!params->fifo_size)
-		params->fifo_size = hw->fifo_size;
+		params->info = hw->info & ~SNDRV_PCM_INFO_FIFO_IN_FRAMES;
+	if (!params->fifo_size) {
+		if (snd_mask_min(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT]) ==
+		    snd_mask_max(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT]) &&
+                    snd_mask_min(&params->masks[SNDRV_PCM_HW_PARAM_CHANNELS]) ==
+                    snd_mask_max(&params->masks[SNDRV_PCM_HW_PARAM_CHANNELS])) {
+			changed = substream->ops->ioctl(substream,
+					SNDRV_PCM_IOCTL1_FIFO_SIZE, params);
+			if (params < 0)
+				return changed;
+		}
+	}
 	params->rmask = 0;
 	return 0;
 }