The code in this library is far from self-explanatory, hopefully this state diagram reverse-engineered from the code will help others understand the expected transitions. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Reviewed-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> Reviewed-by: Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx> Reviewed-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx> --- sound/hda/hdac_stream.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c index 2dbde3d1cf683..2e98f5fd50e54 100644 --- a/sound/hda/hdac_stream.c +++ b/sound/hda/hdac_stream.c @@ -13,6 +13,39 @@ #include <sound/hda_register.h> #include "trace.h" +/* + * the hdac_stream library is intended to be used with the following + * transitions. The states are not formally defined in the code but loosely + * inspired by boolean variables. Note that the 'prepared' field is not used + * in this library but by the callers during the hw_params/prepare transitions + * + * | + * stream_init() | + * v + * +--+-------+ + * | unused | + * +--+----+--+ + * | ^ + * stream_assign() | | stream_release() + * v | + * +--+----+--+ + * | opened | + * +--+----+--+ + * | ^ + * stream_reset() | | + * stream_setup() | | stream_cleanup() + * v | + * +--+----+--+ + * | prepared | + * +--+----+--+ + * | ^ + * stream_start() | | stream_stop() + * v | + * +--+----+--+ + * | running | + * +----------+ + */ + /** * snd_hdac_get_stream_stripe_ctl - get stripe control value * @bus: HD-audio core bus -- 2.34.1
