[alsa-devel] period_time in slave definition

Pavel Hofman pavel.hofman at ivitera.com
Mon Feb 28 13:25:34 CET 2011


According to
http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html , my
.asoundrc contains:

pcm.test {
        type plug
        slave {
                pcm "hw:0"
                format "unchanged"
                channels "unchanged"
                rate "unchanged"
                period_size 1024
                buffer_size 4096

While pcm, format, channels, and rate are accepted, the period and
buffer fields are refused:

ALSA lib pcm.c:6811:(snd_pcm_slave_conf) Unknown field period_time

I checked the source code and the keywords seem to be ok

static const char *const names[SND_PCM_HW_PARAM_LAST_INTERVAL + 1] = {
	[SND_PCM_HW_PARAM_FORMAT] = "format",
	[SND_PCM_HW_PARAM_CHANNELS] = "channels",
	[SND_PCM_HW_PARAM_RATE] = "rate",
	[SND_PCM_HW_PARAM_PERIOD_TIME] = "period_time",
	[SND_PCM_HW_PARAM_PERIOD_SIZE] = "period_size",
	[SND_PCM_HW_PARAM_BUFFER_TIME] = "buffer_time",
	[SND_PCM_HW_PARAM_BUFFER_SIZE] = "buffer_size",

Has any change been introduced recently which is not reflected on wiki
yet? Is there a way to specify "default" period and buffer parameters?

Thanks a lot,


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