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authorTakashi Iwai <tiwai@suse.de>2009-03-19 10:08:49 +0100
committerTakashi Iwai <tiwai@suse.de>2009-03-19 10:08:49 +0100
commitded652f7024bc2d7b6118b561a44187af30841b0 (patch)
tree3d48a4e0c7ea8f176e4e64210da92b06a3f28036
parent5f513e1197f27e9a0bcfec0feaac59f976f4a37e (diff)
ALSA: pcm - Fix delta calculation at boundary overlap
When the hw_ptr_interrupt reaches the boundary, it must check whether the hw_base was already lapped and corret the delta value appropriately. Also, rebasing the hw_ptr needs a correction because buffer_size isn't always aligned to period_size. Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/core/pcm_lib.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 92ed6d819225..063c675177a9 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -221,8 +221,11 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
new_hw_ptr = hw_base + pos;
hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
delta = new_hw_ptr - hw_ptr_interrupt;
- if (hw_ptr_interrupt == runtime->boundary)
- hw_ptr_interrupt = 0;
+ if (hw_ptr_interrupt >= runtime->boundary) {
+ hw_ptr_interrupt %= runtime->boundary;
+ if (!hw_base) /* hw_base was already lapped; recalc delta */
+ delta = new_hw_ptr - hw_ptr_interrupt;
+ }
if (delta < 0) {
delta += runtime->buffer_size;
if (delta < 0) {
@@ -233,6 +236,8 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
(long)hw_ptr_interrupt);
/* rebase to interrupt position */
hw_base = new_hw_ptr = hw_ptr_interrupt;
+ /* align hw_base to buffer_size */
+ hw_base -= hw_base % runtime->buffer_size;
delta = 0;
} else {
hw_base += runtime->buffer_size;