diff options
| author | John Grossman <johngro@google.com> | 2011-07-21 10:59:55 -0700 |
|---|---|---|
| committer | Simon Wilson <simonwilson@google.com> | 2011-07-27 14:59:56 -0700 |
| commit | 3bb114a6459c78ea4e7d2f84568361430f26ff20 (patch) | |
| tree | c70ebb8db726110287cf163dcbe55e982fab73dd | |
| parent | ee99f213b29297b1016bc6210c16085c0b3068de (diff) | |
pcm: add control for ASLA thresholds to pcm_open
Add the ability to explicitly set start, stop and silence thresholds during
tinyalsa's pcm_open. Setting any of these values to 0 in your pcm_config
structure will cause the system to use its old defaults.
| -rw-r--r-- | include/tinyalsa/asoundlib.h | 12 | ||||
| -rw-r--r-- | pcm.c | 16 |
2 files changed, 25 insertions, 3 deletions
diff --git a/include/tinyalsa/asoundlib.h b/include/tinyalsa/asoundlib.h index 8395766..2e8c3e0 100644 --- a/include/tinyalsa/asoundlib.h +++ b/include/tinyalsa/asoundlib.h @@ -59,6 +59,18 @@ struct pcm_config { unsigned int period_size; unsigned int period_count; enum pcm_format format; + + /* Values to use for the ALSA start, stop and silence thresholds. Setting + * any one of these values to 0 will cause the default tinyalsa values to be + * used instead. Tinyalsa defaults are as follows. + * + * start_threshold : period_count * period_size + * stop_threshold : period_count * period_size + * silence_threshold : 0 + */ + unsigned int start_threshold; + unsigned int stop_threshold; + unsigned int silence_threshold; }; /* Mixer control types */ @@ -427,11 +427,21 @@ struct pcm *pcm_open(unsigned int card, unsigned int device, sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE; sparams.period_step = 1; sparams.avail_min = 1; - sparams.start_threshold = config->period_count * config->period_size; - sparams.stop_threshold = config->period_count * config->period_size; + + if (!config->start_threshold) + sparams.start_threshold = config->period_count * config->period_size; + else + sparams.start_threshold = config->start_threshold; + + if (!config->stop_threshold) + sparams.stop_threshold = config->period_count * config->period_size; + else + sparams.stop_threshold = config->stop_threshold; + sparams.xfer_align = config->period_size / 2; /* needed for old kernels */ sparams.silence_size = 0; - sparams.silence_threshold = 0; + sparams.silence_threshold = config->silence_threshold; + if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) { oops(pcm, errno, "cannot set sw params"); |