mirrors/alsa-lib
1
0
Fork 0
mirror of https://github.com/alsa-project/alsa-lib.git synced 2025-11-06 13:29:59 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

pcm: direct: allow users to configure different period sizes

Browse source 
This patch allows the effective period size to be a multiple of the
slave-pcm period size.
Allowing only exact multiple of original period size is achieved by
borrowing code from the kernel hwrules implementation.

This patch is intended to save cpu workload when for example, the
slave operates with very small periods but a user does not need that
small periods.

This feature is enabled by default and can be disabled by adding
config option 'var_periodsize 0'.

Signed-off-by: Alexander Jahn <ajahn@de.adit-jv.com>
Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Joshua Frkuska 2016-12-30 11:56:15 +05:30 • committed by Takashi Iwai
parent 9ed4075f05
commit 0a61c79681
5 changed files with 84 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

88
src/pcm/pcm_direct.c
View file

@ -660,6 +660,29 @@ static int hw_param_interval_refine_minmax(snd_pcm_hw_params_t *params,
return hw_param_interval_refine_one(params, var, &t);
}
/* this code is used 'as-is' from the alsa kernel code */
static int snd_interval_step(struct snd_interval *i, unsigned int min,
unsigned int step)
{
unsigned int n;
int changed = 0;
n = (i->min - min) % step;
if (n != 0 || i->openmin) {
i->min += step - n;
changed = 1;
}
n = (i->max - min) % step;
if (n != 0 || i->openmax) {
i->max -= n;
changed = 1;
}
if (snd_interval_checkempty(i)) {
i->empty = 1;
return -EINVAL;
}
return changed;
}
#undef REFINE_DEBUG
int snd_pcm_direct_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
@ -710,15 +733,16 @@ int snd_pcm_direct_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
&dshare->shmptr->hw.rate);
if (err < 0)
return err;
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_SIZE,
&dshare->shmptr->hw.period_size);
if (err < 0)
return err;
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_TIME,
&dshare->shmptr->hw.period_time);
if (err < 0)
return err;
if (dshare->max_periods < 0) {
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_SIZE,
&dshare->shmptr->hw.period_size);
if (err < 0)
return err;
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_TIME,
&dshare->shmptr->hw.period_time);
if (err < 0)
return err;
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_BUFFER_SIZE,
&dshare->shmptr->hw.buffer_size);
if (err < 0)
@ -730,11 +754,38 @@ int snd_pcm_direct_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
} else if (params->rmask & ((1<<SND_PCM_HW_PARAM_PERIODS)|
(1<<SND_PCM_HW_PARAM_BUFFER_BYTES)|
(1<<SND_PCM_HW_PARAM_BUFFER_SIZE)|
(1<<SND_PCM_HW_PARAM_BUFFER_TIME))) {
(1<<SND_PCM_HW_PARAM_BUFFER_TIME)|
(1<<SND_PCM_HW_PARAM_PERIOD_TIME)|
(1<<SND_PCM_HW_PARAM_PERIOD_SIZE)|
(1<<SND_PCM_HW_PARAM_PERIOD_BYTES))) {
snd_interval_t period_size = dshare->shmptr->hw.period_size;
snd_interval_t period_time = dshare->shmptr->hw.period_time;
int changed;
unsigned int max_periods = dshare->max_periods;
if (max_periods < 2)
max_periods = dshare->slave_buffer_size / dshare->slave_period_size;
/* make sure buffer size does not exceed slave buffer size */
err = hw_param_interval_refine_minmax(params, SND_PCM_HW_PARAM_BUFFER_SIZE,
2 * dshare->slave_period_size, dshare->slave_buffer_size);
if (err < 0)
return err;
if (dshare->var_periodsize) {
/* more tolerant settings... */
if (dshare->shmptr->hw.buffer_size.max / 2 > period_size.max)
period_size.max = dshare->shmptr->hw.buffer_size.max / 2;
if (dshare->shmptr->hw.buffer_time.max / 2 > period_time.max)
period_time.max = dshare->shmptr->hw.buffer_time.max / 2;
}
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_SIZE,
&period_size);
if (err < 0)
return err;
err = hw_param_interval_refine_one(params, SND_PCM_HW_PARAM_PERIOD_TIME,
&period_time);
if (err < 0)
return err;
do {
changed = 0;
err = hw_param_interval_refine_minmax(params, SND_PCM_HW_PARAM_PERIODS,
@ -746,8 +797,16 @@ int snd_pcm_direct_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
if (err < 0)
return err;
changed |= err;
err = snd_interval_step(hw_param_interval(params, SND_PCM_HW_PARAM_PERIOD_SIZE),
0, dshare->slave_period_size);
if (err < 0)
return err;
changed |= err;
if (err)
params->rmask |= (1 << SND_PCM_HW_PARAM_PERIOD_SIZE);
} while (changed);
}
dshare->timer_ticks = hw_param_interval(params, SND_PCM_HW_PARAM_PERIOD_SIZE)->max / dshare->slave_period_size;
params->info = dshare->shmptr->s.info;
#ifdef REFINE_DEBUG
snd_output_puts(log, "DMIX REFINE (end):\n");
@ -1183,6 +1242,7 @@ int snd_pcm_direct_initialize_poll_fd(snd_pcm_direct_t *dmix)
dmix->tread = 1;
dmix->timer_need_poll = 0;
dmix->timer_ticks = 1;
ret = snd_pcm_info(dmix->spcm, &info);
if (ret < 0) {
SNDERR("unable to info for slave pcm");
@ -1366,7 +1426,7 @@ int snd_pcm_direct_set_timer_params(snd_pcm_direct_t *dmix)
snd_timer_params_set_auto_start(&params, 1);
if (dmix->type != SND_PCM_TYPE_DSNOOP)
snd_timer_params_set_early_event(&params, 1);
snd_timer_params_set_ticks(&params, 1);
snd_timer_params_set_ticks(&params, dmix->timer_ticks);
if (dmix->tread) {
filter = (1<<SND_TIMER_EVENT_TICK) |
dmix->timer_events;
@ -1656,6 +1716,7 @@ int snd_pcm_direct_parse_open_conf(snd_config_t *root, snd_config_t *conf,
rec->ipc_gid = -1;
rec->slowptr = 1;
rec->max_periods = 0;
rec->var_periodsize = 1;
/* read defaults */
if (snd_config_search(root, "defaults.pcm.dmix_max_periods", &n) >= 0) {
@ -1762,6 +1823,13 @@ int snd_pcm_direct_parse_open_conf(snd_config_t *root, snd_config_t *conf,
rec->max_periods = val;
continue;
}
if (strcmp(id, "var_periodsize") == 0) {
err = snd_config_get_bool(n);
if (err < 0)
return err;
rec->var_periodsize = err;
continue;
}
SNDERR("Unknown field %s", id);
return -EINVAL;
}