On Sun, 11 Oct 2015 15:33:50 +0200, Takashi Sakamoto wrote:

In firewire-lib, isochronous packet streaming is stopped when detecting wrong value for FMT field of CIP headers. Although this is appropriate to IEC 61883-1 and 6, some BeBoB based devices with vendors' customization use invalid value to FMT field of CIP headers in the beginning of streaming.

$ journalctl snd-bebob fw1.0: Detect unexpected protocol: 01000000 8000ffff

I got this log with M-Audio FireWire 1814. In this line, the value of FMT field is 0x00, while it should be 0x10 in usual AMDTP.

Except for the beginning, these devices continue to transfer packets with valid value for FMT field, except for the beginning. Therefore, in this case, firewire-lib should continue to process packets. The former implementation of firewire-lib performs it.

This commit loosens the handling of wrong value, to continue packet processing in the case.

Fixes: 414ba022a528('ALSA: firewire-lib: add support arbitrary value for fmt/fdf fields in CIP header') Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp

Applied, thanks.

Takashi

---

sound/firewire/amdtp-stream.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index fa10b58..ed29026 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -468,10 +468,12 @@ static int handle_in_packet(struct amdtp_stream *s, /* Check valid protocol or not. */ fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT; if (fmt != s->fmt) {

• dev_err(&s->unit->device,
  

• 	"Detect unexpected protocol: %08x %08x\n",
  

• 	cip_header[0], cip_header[1]);
  

• return -EIO;
  

• dev_info_ratelimited(&s->unit->device,
  

• 		     "Detect unexpected protocol: %08x %08x\n",
  

• 		     cip_header[0], cip_header[1]);
  

• *data_blocks = 0;
  

• pcm_frames = 0;
  

• goto end;
  

  }

  /* Calculate data blocks */

-- 2.1.4