Commit c09010ee authored May 18, 2021 by Takashi Sakamoto Committed by Takashi Iwai May 18, 2021

ALSA: firewire-lib: handle the case that empty isochronous packet payload for CIP



Two quadlets are at least included in isochronous packet payload for
Common Isochronous Packet (CIP) format in IEC 61883-1. However, it's
better to equip ALSA IEC 61883-1/6 packet streaming engine for contrary
packet.

This commit handles isochronous cycle to process such packet so that the
cycle is skipped.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-3-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 6d60b7a3

sound/firewire/amdtp-stream.c

+12 −5

Original line number	Diff line number	Diff line
		@@ -656,11 +656,18 @@ static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
		}

		if (cip_header_size > 0) {
		if (*payload_length >= cip_header_size) {
		cip_header = ctx_header + 2;
		err = check_cip_header(s, cip_header, *payload_length,
		data_blocks, data_block_counter, syt);
		err = check_cip_header(s, cip_header, *payload_length, data_blocks,
		data_block_counter, syt);
		if (err < 0)
		return err;
		} else {
		// Handle the cycle so that empty packet arrives.
		cip_header = NULL;
		*data_blocks = 0;
		*syt = 0;
		}
		} else {
		cip_header = NULL;
		err = 0;