From ded652f7024bc2d7b6118b561a44187af30841b0 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 19 Mar 2009 10:08:49 +0100 Subject: [PATCH] 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 --- sound/core/pcm_lib.c | 9 +++++++-- 1 file 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;