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Commit a105f642 authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: fireworks: perform sequence replay for media clock recovery


Echo Digital Audio Corporation had US patent US7599388B2 titled as
'System and method for high-bandwidth serial bus data transfer'. In the
patent, dual-banked shared memory is used to deliver data between
serial bus transmission and processor in FIFO way. The patent seems to be
used for Fireworks board module. The mechanism is not compliant to
synchronization based on presentation time expressed in syt field
of CIP header. Fireworks board module takes care of the sequence of
the number of data blocks per packet and just ignores the value of syt
field.

This commit takes fireworks driver to performs sequence replay for media
clock recovery. As long as I tested, Audiofire 2 and 4 have a quirk to
skip an isochronous cycle several thousands after starting packet
transmission.

The sequence replay is tested with below models:
 * Loud Technology Mackie 400f
 * Echo Audio Audiofire 12 (DSP model)
 * Echo Audio Audiofire 12 (FPGA model)
 * Echo Audio Audiofire 8 (DSP model)
 * Echo Audio Audiofire 8 (FPGA model)
 * Echo Audio Audiofire Pre8
 * Echo Audio Audiofire 4
 * Echo Audio Audiofire 2

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210531025103.17880-3-o-takashi@sakamocchi.jp


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 77f1fd6d
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