mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
ALSA: firewire-lib: add PCM rules to obsolete PCM constraints based on LCM of SYT_INTERVAL
In blocking mode of IEC 61883-1/6, when one isochronous packet includes data for events, the data is for the same number of events as SYT_INTERVAL decided according to sampling transmission frequency (SFC). IEC 61883-1/6 engine of ALSA firewire stack applies constraints of period and buffer size of PCM intermediate buffer of PCM substream. At present, this constraint is designed to round the size up/down to 32 frames. This value comes from the least common multiple (LCM) of SYT_INTERVAL. Although this looks to work well, in lower sampling rate, applications are not allowed to set size of period quite near period time constraint (at present 5 msec per period). This commit adds PCM rules for period/buffer size and rate to obsoletes the constraints based on LCM. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
parent
96395e86e3
commit
5950229582
1 changed files with 71 additions and 7 deletions
|
@ -140,6 +140,59 @@ const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
|
|||
};
|
||||
EXPORT_SYMBOL(amdtp_rate_table);
|
||||
|
||||
static int apply_constraint_to_size(struct snd_pcm_hw_params *params,
|
||||
struct snd_pcm_hw_rule *rule)
|
||||
{
|
||||
struct snd_interval *s = hw_param_interval(params, rule->var);
|
||||
const struct snd_interval *r =
|
||||
hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
|
||||
struct snd_interval t = {
|
||||
.min = s->min, .max = s->max, .integer = 1,
|
||||
};
|
||||
int i;
|
||||
|
||||
for (i = 0; i < CIP_SFC_COUNT; ++i) {
|
||||
unsigned int rate = amdtp_rate_table[i];
|
||||
unsigned int step = amdtp_syt_intervals[i];
|
||||
|
||||
if (!snd_interval_test(r, rate))
|
||||
continue;
|
||||
|
||||
t.min = roundup(t.min, step);
|
||||
t.max = rounddown(t.max, step);
|
||||
}
|
||||
|
||||
if (snd_interval_checkempty(&t))
|
||||
return -EINVAL;
|
||||
|
||||
return snd_interval_refine(s, &t);
|
||||
}
|
||||
|
||||
static int apply_constraint_to_rate(struct snd_pcm_hw_params *params,
|
||||
struct snd_pcm_hw_rule *rule)
|
||||
{
|
||||
struct snd_interval *r =
|
||||
hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
|
||||
const struct snd_interval *s = hw_param_interval_c(params, rule->deps[0]);
|
||||
struct snd_interval t = {
|
||||
.min = UINT_MAX, .max = 0, .integer = 1,
|
||||
};
|
||||
int i;
|
||||
|
||||
for (i = 0; i < CIP_SFC_COUNT; ++i) {
|
||||
unsigned int step = amdtp_syt_intervals[i];
|
||||
unsigned int rate = amdtp_rate_table[i];
|
||||
|
||||
if (s->min % step || s->max % step)
|
||||
continue;
|
||||
|
||||
t.min = min(t.min, rate);
|
||||
t.max = max(t.max, rate);
|
||||
}
|
||||
|
||||
return snd_interval_refine(r, &t);
|
||||
}
|
||||
|
||||
/**
|
||||
* amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
|
||||
* @s: the AMDTP stream, which must be initialized.
|
||||
|
@ -194,16 +247,27 @@ int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
|
|||
* number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
|
||||
* depending on its sampling rate. For accurate period interrupt, it's
|
||||
* preferrable to align period/buffer sizes to current SYT_INTERVAL.
|
||||
*
|
||||
* TODO: These constraints can be improved with proper rules.
|
||||
* Currently apply LCM of SYT_INTERVALs.
|
||||
*/
|
||||
err = snd_pcm_hw_constraint_step(runtime, 0,
|
||||
SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 32);
|
||||
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
|
||||
apply_constraint_to_size, NULL,
|
||||
SNDRV_PCM_HW_PARAM_RATE, -1);
|
||||
if (err < 0)
|
||||
goto end;
|
||||
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
|
||||
apply_constraint_to_rate, NULL,
|
||||
SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
|
||||
if (err < 0)
|
||||
goto end;
|
||||
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
|
||||
apply_constraint_to_size, NULL,
|
||||
SNDRV_PCM_HW_PARAM_RATE, -1);
|
||||
if (err < 0)
|
||||
goto end;
|
||||
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
|
||||
apply_constraint_to_rate, NULL,
|
||||
SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
|
||||
if (err < 0)
|
||||
goto end;
|
||||
err = snd_pcm_hw_constraint_step(runtime, 0,
|
||||
SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 32);
|
||||
end:
|
||||
return err;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue