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>
This commit is contained in:
Takashi Sakamoto 2021-05-18 22:00:41 +09:00 committed by Takashi Iwai
parent 6d60b7a3d3
commit c09010eeb3

View File

@ -656,11 +656,18 @@ static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
}
if (cip_header_size > 0) {
cip_header = ctx_header + 2;
err = check_cip_header(s, cip_header, *payload_length,
data_blocks, data_block_counter, syt);
if (err < 0)
return err;
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);
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;