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ALSA: firewire-lib: fix initial value of data block count for IR context without CIP_DBC_IS_END_EVENT 

For IR context, ALSA IEC 61883-1/6 engine uses initial value of data
block counter as UINT_MAX, to detect first isochronous packet in the
middle of packet streaming.

At present, when CIP_DBC_IS_END_EVENT is not used (i.e. for drivers except
for ALSA fireworks driver), the initial value is used as is for
tracepoints event. However, the engine can detect the value of dbc field
in the payload of first isochronous packet and the value should be assigned
to the event.

This commit fixes the bug.

Fixes: 76864868db ("ALSA: firewire-lib: cache next data_block_counter after probing tracepoints event for IR context")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2019-07-07 21:07:55 +09:00 committed by Takashi Iwai
parent 7fbf909668
commit 4ece7f6fd8
1 changed files with 4 additions and 2 deletions
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6
sound/firewire/amdtp-stream.c
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@ -654,8 +654,10 @@ static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
*dbc = 0;
}
if (err >= 0 && s->flags & CIP_DBC_IS_END_EVENT)
s->data_block_counter = *dbc;
if (err < 0)
return err;
s->data_block_counter = *dbc;
trace_amdtp_packet(s, cycle, cip_header, *payload_length, *data_blocks,
index);