diff options
| -rw-r--r-- | sound/drivers/aloop.c | 62 |
1 files changed, 35 insertions, 27 deletions
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index ad079b63b8ba..8b5c36f4d303 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -117,6 +117,7 @@ struct loopback_pcm { /* timer stuff */ unsigned int irq_pos; /* fractional IRQ position */ unsigned int period_size_frac; + unsigned int last_drift; unsigned long last_jiffies; struct timer_list timer; }; @@ -264,6 +265,7 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) return err; dpcm->last_jiffies = jiffies; dpcm->pcm_rate_shift = 0; + dpcm->last_drift = 0; spin_lock(&cable->lock); cable->running |= stream; cable->pause &= ~stream; @@ -444,34 +446,30 @@ static void copy_play_buf(struct loopback_pcm *play, } } -#define BYTEPOS_UPDATE_POSONLY 0 -#define BYTEPOS_UPDATE_CLEAR 1 -#define BYTEPOS_UPDATE_COPY 2 - -static void loopback_bytepos_update(struct loopback_pcm *dpcm, - unsigned int delta, - unsigned int cmd) +static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, + unsigned int jiffies_delta) { - unsigned int count; unsigned long last_pos; + unsigned int delta; last_pos = byte_pos(dpcm, dpcm->irq_pos); - dpcm->irq_pos += delta * dpcm->pcm_bps; - count = byte_pos(dpcm, dpcm->irq_pos) - last_pos; - if (!count) - return; - if (cmd == BYTEPOS_UPDATE_CLEAR) - clear_capture_buf(dpcm, count); - else if (cmd == BYTEPOS_UPDATE_COPY) - copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK], - dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE], - count); - dpcm->buf_pos += count; - dpcm->buf_pos %= dpcm->pcm_buffer_size; + dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; + delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; + if (delta >= dpcm->last_drift) + delta -= dpcm->last_drift; + dpcm->last_drift = 0; if (dpcm->irq_pos >= dpcm->period_size_frac) { dpcm->irq_pos %= dpcm->period_size_frac; dpcm->period_update_pending = 1; } + return delta; +} + +static inline void bytepos_finish(struct loopback_pcm *dpcm, + unsigned int delta) +{ + dpcm->buf_pos += delta; + dpcm->buf_pos %= dpcm->pcm_buffer_size; } static unsigned int loopback_pos_update(struct loopback_cable *cable) @@ -481,7 +479,7 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable) struct loopback_pcm *dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE]; unsigned long delta_play = 0, delta_capt = 0; - unsigned int running; + unsigned int running, count1, count2; unsigned long flags; spin_lock_irqsave(&cable->lock, flags); @@ -500,12 +498,13 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable) goto unlock; if (delta_play > delta_capt) { - loopback_bytepos_update(dpcm_play, delta_play - delta_capt, - BYTEPOS_UPDATE_POSONLY); + count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); + bytepos_finish(dpcm_play, count1); delta_play = delta_capt; } else if (delta_play < delta_capt) { - loopback_bytepos_update(dpcm_capt, delta_capt - delta_play, - BYTEPOS_UPDATE_CLEAR); + count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); + clear_capture_buf(dpcm_capt, count1); + bytepos_finish(dpcm_capt, count1); delta_capt = delta_play; } @@ -513,8 +512,17 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable) goto unlock; /* note delta_capt == delta_play at this moment */ - loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY); - loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY); + count1 = bytepos_delta(dpcm_play, delta_play); + count2 = bytepos_delta(dpcm_capt, delta_capt); + if (count1 < count2) { + dpcm_capt->last_drift = count2 - count1; + count1 = count2; + } else if (count1 > count2) { + dpcm_play->last_drift = count1 - count2; + } + copy_play_buf(dpcm_play, dpcm_capt, count1); + bytepos_finish(dpcm_play, count1); + bytepos_finish(dpcm_capt, count1); unlock: spin_unlock_irqrestore(&cable->lock, flags); return running; |