At Tue, 22 May 2012 14:54:02 -0500, Pierre-Louis Bossart wrote:
Group read of hw_ptr, tstamp and jiffies in a sequence for better correlation. Previous code took timestamp at the end, which could introduce delays between audio time and system time.
Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com
Applied this one. Thanks.
Takashi
sound/core/pcm_lib.c | 23 ++++++++++++++++++----- 1 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index ae46d75..3f3097d 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -313,9 +313,22 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_base; snd_pcm_sframes_t hdelta, delta; unsigned long jdelta;
unsigned long curr_jiffies;
struct timespec curr_tstamp;
old_hw_ptr = runtime->status->hw_ptr;
/*
* group pointer, time and jiffies reads to allow for more* accurate correlations/corrections.* The values are stored at the end of this routine after* corrections for hw_ptr position*/pos = substream->ops->pointer(substream);
curr_jiffies = jiffies;
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp);if (pos == SNDRV_PCM_POS_XRUN) { xrun(substream); return -EPIPE;
@@ -343,7 +356,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, delta = runtime->hw_ptr_interrupt + runtime->period_size; if (delta > new_hw_ptr) { /* check for double acknowledged interrupts */
hdelta = jiffies - runtime->hw_ptr_jiffies;
hdelta = curr_jiffies - runtime->hw_ptr_jiffies; if (hdelta > runtime->hw_ptr_buffer_jiffies/2) { hw_base += runtime->buffer_size; if (hw_base >= runtime->boundary)@@ -388,7 +401,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, * Without regular period interrupts, we have to check * the elapsed time to detect xruns. */
jdelta = jiffies - runtime->hw_ptr_jiffies;
jdelta = curr_jiffies - runtime->hw_ptr_jiffies;@@ -430,7 +443,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, if (hdelta < runtime->delay) goto no_jiffies_check; hdelta -= runtime->delay;
- jdelta = jiffies - runtime->hw_ptr_jiffies;
- jdelta = curr_jiffies - runtime->hw_ptr_jiffies; if (((hdelta * HZ) / runtime->rate) > jdelta + HZ/100) { delta = jdelta / (((runtime->period_size * HZ) / runtime->rate)
@@ -492,9 +505,9 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, } runtime->hw_ptr_base = hw_base; runtime->status->hw_ptr = new_hw_ptr;
- runtime->hw_ptr_jiffies = jiffies;
- runtime->hw_ptr_jiffies = curr_jiffies; if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
runtime->status->tstamp = curr_tstamp;return snd_pcm_update_state(substream, runtime);
}
1.7.6.5