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pcm: rate: fix the hw_ptr update until the boundary available

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For long time test case, the slave_hw_ptr will exceed the boundary
and wraparound the slave_hw_ptr. This slave boundary wraparound will
cause the rate->hw_ptr to wraparound irrespective of the
rate->boundary availability and due to that the available size goes
wrong.

Hence, to get the correct available size,
- Its necessary to increment the rate->hw_ptr upto the rate->boundary
and then wraparound the rate->hw_ptr.
- While handling fraction part of slave period, rounded value will be
introduced by input_frames(). To eliminate rounding issue on
rate->hw_ptr, subtract last rounded value from rate->hw_ptr and add
new rounded value of present slave_hw_ptr fraction part to
rate->hw_ptr.

Signed-off-by: mahendran.k <mahendran.kuppusamy@in.bosch.com>
Signed-off-by: Mounesh Sutar <mounesh_sutar@mentor.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
mahendran.k 2016-12-30 11:59:27 +05:30 • committed by Takashi Iwai
parent 8eeee1ab7d
commit 7570e5d775
1 changed files with 25 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

31
src/pcm/pcm_rate.c
View file

@ -50,7 +50,7 @@ typedef struct _snd_pcm_rate snd_pcm_rate_t;
struct _snd_pcm_rate {
snd_pcm_generic_t gen;
snd_pcm_uframes_t appl_ptr, hw_ptr;
snd_pcm_uframes_t appl_ptr, hw_ptr, last_slave_hw_ptr;
snd_pcm_uframes_t last_commit_ptr;
snd_pcm_uframes_t orig_avail_min;
snd_pcm_sw_params_t sw_params;
@ -563,14 +563,31 @@ static inline void snd_pcm_rate_sync_hwptr0(snd_pcm_t *pcm, snd_pcm_uframes_t sl
{
snd_pcm_rate_t *rate = pcm->private_data;
snd_pcm_sframes_t slave_hw_ptr_diff = slave_hw_ptr - rate->last_slave_hw_ptr;
snd_pcm_sframes_t last_slave_hw_ptr_frac;
if (pcm->stream != SND_PCM_STREAM_PLAYBACK)
return;
/* FIXME: boundary overlap of slave hw_ptr isn't evaluated here!
* e.g. if slave rate is small...
if (slave_hw_ptr_diff < 0)
slave_hw_ptr_diff += rate->gen.slave->boundary; /* slave boundary wraparound */
else if (slave_hw_ptr_diff == 0)
return;
last_slave_hw_ptr_frac = rate->last_slave_hw_ptr % rate->gen.slave->period_size;
/* While handling fraction part fo slave period, rounded value will be
* introduced by input_frames().
* To eliminate rounding issue on rate->hw_ptr, subtract last rounded
* value from rate->hw_ptr and add new rounded value of present
* slave_hw_ptr fraction part to rate->hw_ptr. Hence,
* rate->hw_ptr += [ (no. of updated slave periods * pcm rate period size) -
* fractional part of last_slave_hw_ptr rounded value +
* fractional part of updated slave hw ptr's rounded value ]
*/
rate->hw_ptr =
(slave_hw_ptr / rate->gen.slave->period_size) * pcm->period_size +
rate->ops.input_frames(rate->obj, slave_hw_ptr % rate->gen.slave->period_size);
rate->hw_ptr += (
(((last_slave_hw_ptr_frac + slave_hw_ptr_diff) / rate->gen.slave->period_size) * pcm->period_size) -
rate->ops.input_frames(rate->obj, last_slave_hw_ptr_frac) +
rate->ops.input_frames(rate->obj, (last_slave_hw_ptr_frac + slave_hw_ptr_diff) % rate->gen.slave->period_size));
rate->last_slave_hw_ptr = slave_hw_ptr;
rate->hw_ptr %= pcm->boundary;
}
@ -635,6 +652,7 @@ static int snd_pcm_rate_prepare(snd_pcm_t *pcm)
return err;
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
rate->last_slave_hw_ptr = 0;
err = snd_pcm_rate_init(pcm);
if (err < 0)
return err;
@ -650,6 +668,7 @@ static int snd_pcm_rate_reset(snd_pcm_t *pcm)
return err;
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
rate->last_slave_hw_ptr = 0;
err = snd_pcm_rate_init(pcm);
if (err < 0)
return err;