[alsa-devel] [PATCH v1 0/3] Allow reconfiguration of clock rate

Jiada Wang jiada_wang at mentor.com
Mon Jul 22 09:24:00 CEST 2019


There is use case in Gstreamer ALSA sink, in case of changed caps
Gsreatmer reconfigs and it calls snd_pcm_hw_free() before snd_pcm_prepre().
See gstreamer1.0-plugins-base/
gst-libs/gst/audio/gstaudiobasesink.c: gst_audio_base_sink_setcaps():
- gst_audio_ring_buffer_release()
- gst_audio_sink_ring_buffer_release()
- gst_alsasink_unprepare()
- snd_pcm_hw_free()
is called before
- gst_audio_ring_buffer_acquire()
- gst_audio_sink_ring_buffer_acquire()
- gst_alsasink_prepare()
- set_hwparams()
- snd_pcm_hw_params()
- snd_pcm_prepare()

But with current implementation after clock rate is started in .prepare
reconfiguration of clock rate is not allowed, unless the stream is stopped.

This patch set by move stop of clock to .hw_free callback,
to allow reconfiguration of clock rate.

Jiada Wang (1):
  ASoC: rsnd: call .hw_{params,free} in pair for same stream

Timo Wischer (2):
  ASoC: rsnd: Support hw_free() callback at DAI level
  ASoC: rsnd: Allow reconfiguration of clock rate

 sound/soc/sh/rcar/core.c | 22 +++++++++++++--
 sound/soc/sh/rcar/rsnd.h | 36 ++++++++++++++++++++----
 sound/soc/sh/rcar/ssi.c  | 61 +++++++++++++++++++++++++++++-----------
 sound/soc/sh/rcar/ssiu.c |  3 +-
 4 files changed, 96 insertions(+), 26 deletions(-)

-- 
2.19.2



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