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In design of audio and music unit in IEEE 1394 bus, feedback of effective sampling transfer frequency (STF) is delivered by packets transferred from device. The devices supported by ALSA firewire stack are categorized to three groups regarding to it. * Group 1: * Echo Audio Fireworks board module * Oxford Semiconductor OXFW971 ASIC * Digidesign Digi00x family * Tascam FireWire series * RME Fireface series * Group 2: * BridgeCo. DM1000/DM1100/DM1500 ASICs for BeBoB solution * TC Applied Technologies DICE ASICs * Group 3: * Mark of the Unicord FireWire series In group 1, the effective STF is determined by the sequence of the number of events per packet. In group 2, the sequence of presentation timestamp expressed in syt field of CIP header is interpreted as well. In group 3, the presentation timestamp is expressed in source packet header (SPH) of each data block. I note that some models doesn't take care of effective STF with large internal buffer. It's reasonable to name it as group 0: * Group 0 * Oxford Semiconductor OXFW970 ASIC The effective STF is known to be slightly different from nominal STF for all of devices, and to be different between the devices. Furthermore, the effective STF is known to be shifted for long-period transmission. This makes it hard for software to satisfy the effective STF when processing packets to the device. The effective STF is deterministic as a result of analyzing the batch of packet transferred from the device. For the analysis, caching the sequence of parameter in the packet is required. This commit adds an option so that AMDTP domain structure takes AMDTP stream structure to cache the sequence of parameters in packet transferred from the device. The parameters are offset ticks of syt field against the cycle to receive the packet and the number of data blocks per packet. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Link: https://lore.kernel.org/r/20210527122611.173711-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| .. | ||
| amdtp-tascam.c | ||
| Makefile | ||
| tascam-hwdep.c | ||
| tascam-midi.c | ||
| tascam-pcm.c | ||
| tascam-proc.c | ||
| tascam-stream.c | ||
| tascam-transaction.c | ||
| tascam.c | ||
| tascam.h | ||