In ALSA PCM interface, some parameters are used to configure runtime of
PCM substream independently of actual hardware. These parameters are
mainly used to decide the detailed timing to start/stop PCM substream and
release I/O blocking state of application. These parameters are
represented and delivered by a structure.
In alsa-lib PCM API, the structure is hidden from userspace applications.
The applications can set/get actual parameters by helper functions.
In aplay, three of the parameters are configurable. This commit adds
support for them. When no options are given, default values are used.
Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
axfer/options.c | 11 +++++++-
axfer/options.h | 4 +++
axfer/xfer-libasound.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 86 insertions(+), 3 deletions(-)
diff --git a/axfer/options.c b/axfer/options.c
index 5d5dda89..aaeba5f2 100644
--- a/axfer/options.c
+++ b/axfer/options.c
@@ -322,7 +322,7 @@ void context_options_calculate_duration(struct context_options *opts,
int context_options_init(struct context_options *opts, int argc,
char *const *argv, snd_pcm_stream_t direction)
{
- static const char *s_opts = "hvqd:s:t:ID:f:c:r:NMF:B:";
+ static const char *s_opts = "hvqd:s:t:ID:f:c:r:NMF:B:A:R:T:";
static const struct option l_opts[] = {
/* For generic purposes. */
{"help", 0, 0, 'h'},
@@ -345,6 +345,9 @@ int context_options_init(struct context_options *opts, int argc,
{"buffer-time", 1, 0, 'B'},
{"period-size", 1, 0, OPT_PERIOD_SIZE},
{"buffer-size", 1, 0, OPT_BUFFER_SIZE},
+ {"avail-min", 1, 0, 'A'},
+ {"start-delay", 1, 0, 'R'},
+ {"stop-delay", 1, 0, 'T'},
/* For debugging. */
{"dump-hw-params", 0, 0, OPT_DUMP_HW_PARAMS},
{"fatal-errors", 0, 0, OPT_FATAL_ERRORS},
@@ -400,6 +403,12 @@ int context_options_init(struct context_options *opts, int argc,
opts->frames_per_period = parse_l(optarg, &err);
else if (c == OPT_BUFFER_SIZE)
opts->frames_per_buffer = parse_l(optarg, &err);
+ else if (c == 'A')
+ opts->msec_for_avail_min = parse_l(optarg, &err);
+ else if (c == 'R')
+ opts->msec_for_start_threshold = parse_l(optarg, &err);
+ else if (c == 'T')
+ opts->msec_for_stop_threshold = parse_l(optarg, &err);
else if (c == OPT_DUMP_HW_PARAMS)
opts->dump_hw_params = true;
else if (c == OPT_FATAL_ERRORS)
diff --git a/axfer/options.h b/axfer/options.h
index f4ac6c64..63b36364 100644
--- a/axfer/options.h
+++ b/axfer/options.h
@@ -41,6 +41,10 @@ struct context_options {
unsigned int frames_per_period;
unsigned int frames_per_buffer;
+ unsigned int msec_for_avail_min;
+ unsigned int msec_for_start_threshold;
+ unsigned int msec_for_stop_threshold;
+
/* For debugging. */
bool dump_hw_params;
bool finish_at_xrun;
diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c
index 54c58b04..40222e91 100644
--- a/axfer/xfer-libasound.c
+++ b/axfer/xfer-libasound.c
@@ -338,8 +338,76 @@ static int retrieve_actual_hw_params(snd_pcm_hw_params_t *hw_params,
static int configure_sw_params(struct libasound_state *state,
unsigned int frames_per_second,
- unsigned int frames_per_buffer)
+ unsigned int frames_per_buffer,
+ unsigned int msec_for_avail_min,
+ unsigned int msec_for_start_threshold,
+ unsigned int msec_for_stop_threshold)
{
+ snd_pcm_uframes_t frame_count;
+ int err;
+
+ if (msec_for_avail_min > 0) {
+ frame_count = msec_for_avail_min * frames_per_second / 1000000;
+ if (frame_count == 0 || frame_count > frames_per_buffer) {
+ logging(state,
+ _("The msec for 'avail_min' is too %s: %u "
+ "msec (%lu frames at %u).\n"),
+ frame_count == 0 ? "small" : "large",
+ msec_for_avail_min, frame_count,
+ frames_per_second);
+ return -EINVAL;
+ }
+ err = snd_pcm_sw_params_set_avail_min(state->handle,
+ state->sw_params, frame_count);
+ if (err < 0) {
+ logging(state,
+ _("Fail to configure 'avail-min'.\n"));
+ return -EINVAL;
+ }
+ }
+
+ if (msec_for_start_threshold > 0) {
+ frame_count = msec_for_start_threshold * frames_per_second /
+ 1000000;
+ if (frame_count == 0 || frame_count > frames_per_buffer) {
+ logging(state,
+ _("The msec for 'start-delay' is too %s: %u "
+ "msec (%lu frames at %u).\n"),
+ frame_count == 0 ? "small" : "large",
+ msec_for_start_threshold, frame_count,
+ frames_per_second);
+ return -EINVAL;
+ }
+ err = snd_pcm_sw_params_set_start_threshold(state->handle,
+ state->sw_params, frame_count);
+ if (err < 0) {
+ logging(state,
+ _("Fail to configure 'start-delay'.\n"));
+ return -EINVAL;
+ }
+ }
+
+ if (msec_for_stop_threshold > 0) {
+ frame_count = msec_for_stop_threshold * frames_per_second /
+ 1000000;
+ if (frame_count == 0 || frame_count > frames_per_buffer) {
+ logging(state,
+ _("The msec for 'stop-delay' is too %s: %u "
+ "msec (%lu frames at %u).\n"),
+ frame_count == 0 ? "small" : "large",
+ msec_for_stop_threshold, frame_count,
+ frames_per_second);
+ return -EINVAL;
+ }
+ err = snd_pcm_sw_params_set_stop_threshold(state->handle,
+ state->sw_params, frame_count);
+ if (err < 0) {
+ logging(state,
+ _("Fail to configure 'stop-delay'.\n"));
+ return -EINVAL;
+ }
+ }
+
return snd_pcm_sw_params(state->handle, state->sw_params);
}
@@ -404,7 +472,9 @@ static int xfer_libasound_pre_process(struct xfer_context *xfer,
return err;
err = configure_sw_params(state, *frames_per_second,
- *frames_per_buffer);
+ *frames_per_buffer, opts->msec_for_avail_min,
+ opts->msec_for_start_threshold,
+ opts->msec_for_stop_threshold);
if (err < 0) {
logging(state, _("Current software parameters:\n"));
snd_pcm_sw_params_dump(state->sw_params, state->log);
--
2.11.0
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