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ALSA: pcxhr: Fix a counter wrap

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fix a counter wrap to avoid resynchronization of stream positions every several
minutes. The resynchronization may create stream position jitter

Signed-off-by: Markus Bollinger <bollinger@digigram.com>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Markus Bollinger 2012-06-20 08:32:48 +02:00 committed by Takashi Iwai
parent e0815f35cc
commit d7dc9e32ae
1 changed files with 15 additions and 8 deletions
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23
sound/pci/pcxhr/pcxhr_core.c
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@ -1133,13 +1133,12 @@ static u_int64_t pcxhr_stream_read_position(struct pcxhr_mgr *mgr,
hw_sample_count = ((u_int64_t)rmh.stat[0]) << 24;
hw_sample_count += (u_int64_t)rmh.stat[1];
snd_printdd("stream %c%d : abs samples real(%ld) timer(%ld)\n",
snd_printdd("stream %c%d : abs samples real(%llu) timer(%llu)\n",
stream->pipe->is_capture ? 'C' : 'P',
stream->substream->number,
(long unsigned int)hw_sample_count,
(long unsigned int)(stream->timer_abs_periods +
stream->timer_period_frag +
mgr->granularity));
hw_sample_count,
stream->timer_abs_periods + stream->timer_period_frag +
mgr->granularity);
return hw_sample_count;
}
@ -1243,10 +1242,18 @@ irqreturn_t pcxhr_interrupt(int irq, void *dev_id)
if ((dsp_time_diff < 0) &&
(mgr->dsp_time_last != PCXHR_DSP_TIME_INVALID)) {
snd_printdd("ERROR DSP TIME old(%d) new(%d) -> "
"resynchronize all streams\n",
/* handle dsp counter wraparound without resync */
int tmp_diff = dsp_time_diff + PCXHR_DSP_TIME_MASK + 1;
snd_printdd("WARNING DSP timestamp old(%d) new(%d)",
mgr->dsp_time_last, dsp_time_new);
mgr->dsp_time_err++;
if (tmp_diff > 0 && tmp_diff <= (2*mgr->granularity)) {
snd_printdd("-> timestamp wraparound OK: "
"diff=%d\n", tmp_diff);
dsp_time_diff = tmp_diff;
} else {
snd_printdd("-> resynchronize all streams\n");
mgr->dsp_time_err++;
}
}
#ifdef CONFIG_SND_DEBUG_VERBOSE
if (dsp_time_diff == 0)