On Sun, 30 Sep 2018 21:11:49 +0200, Takashi Sakamoto wrote:
In blocking mode of IEC 61883-1/6, when one isochronous packet includes data for events, the data is for the same number of events as SYT_INTERVAL decided according to sampling transmission frequency (SFC).
IEC 61883-1/6 engine of ALSA firewire stack applies constraints of period and buffer size of PCM intermediate buffer of PCM substream. At present, this constraint is designed to round the size up/down to 32 frames. This value comes from the least common multiple (LCM) of SYT_INTERVAL. Although this looks to work well, in lower sampling rate, applications are not allowed to set size of period quite near period time constraint (at present 5 msec per period).
This commit adds PCM rules for period/buffer size and rate to obsoletes the constraints based on LCM.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
Applied, thanks.
Takashi