diff options
Diffstat (limited to 'sound/firewire')
| -rw-r--r-- | sound/firewire/amdtp-stream.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 46f1167bf69f..4d86da0355ba 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -566,6 +566,13 @@ static inline u32 increment_cycle_count(u32 cycle, unsigned int addend) return cycle; } +static inline u32 decrement_cycle_count(u32 cycle, unsigned int subtrahend) +{ + if (cycle < subtrahend) + cycle += 8 * CYCLES_PER_SECOND; + return cycle - subtrahend; +} + static void out_stream_callback(struct fw_iso_context *context, u32 tstamp, size_t header_length, void *header, void *private_data) @@ -607,6 +614,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, unsigned int payload_quadlets, max_payload_quadlets; unsigned int data_blocks; __be32 *buffer, *headers = header; + u32 cycle; if (s->packet_index < 0) return; @@ -614,10 +622,16 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, /* The number of packets in buffer */ packets = header_length / IN_PACKET_HEADER_SIZE; + cycle = compute_cycle_count(tstamp); + + /* Align to actual cycle count for the last packet. */ + cycle = decrement_cycle_count(cycle, packets); + /* For buffer-over-run prevention. */ max_payload_quadlets = amdtp_stream_get_max_payload(s) / 4; for (p = 0; p < packets; p++) { + cycle = increment_cycle_count(cycle, 1); buffer = s->buffer.packets[s->packet_index].buffer; /* The number of quadlets in this packet */ |