From 1be4f21d9984fa9835fae5411a29465dc5aece6f Mon Sep 17 00:00:00 2001

From: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Date: Thu, 13 May 2021 21:56:51 +0900

Subject: [PATCH] ALSA: firewire-lib: fix calculation for size of IR context payload

Git-commit: 1be4f21d9984fa9835fae5411a29465dc5aece6f

Patch-mainline: v5.13-rc3

References: git-fixes

The quadlets for CIP header is handled as a part of IR context header,

thus it doesn't join in IR context payload. However current calculation

includes the quadlets in IR context payload.

Cc: <stable@vger.kernel.org>

Fixes: f11453c7cc01 ("ALSA: firewire-lib: use 16 bytes IR context header to separate CIP header")

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Link: https://lore.kernel.org/r/20210513125652.110249-5-o-takashi@sakamocchi.jp

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

---

 sound/firewire/amdtp-stream.c |   13 ++++++-------

 1 file changed, 6 insertions(+), 7 deletions(-)

--- a/sound/firewire/amdtp-stream.c

+++ b/sound/firewire/amdtp-stream.c

@@ -889,23 +889,22 @@ int amdtp_stream_start(struct amdtp_stre

 		s->ctx_data.rx.last_syt_offset = TICKS_PER_CYCLE;

 	}

-	/* initialize packet buffer */

+	// initialize packet buffer.

+	max_ctx_payload_size = amdtp_stream_get_max_payload(s);

 	if (s->direction == AMDTP_IN_STREAM) {

 		dir = DMA_FROM_DEVICE;

 		type = FW_ISO_CONTEXT_RECEIVE;

-		if (!(s->flags & CIP_NO_HEADER))

+		if (!(s->flags & CIP_NO_HEADER)) {

+			max_ctx_payload_size -= 8;

 			ctx_header_size = IR_CTX_HEADER_SIZE_CIP;

-		else

+		} else {

 			ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;

-

-		max_ctx_payload_size = amdtp_stream_get_max_payload(s) -

-				       ctx_header_size;

+		}

 	} else {

 		dir = DMA_TO_DEVICE;

 		type = FW_ISO_CONTEXT_TRANSMIT;

 		ctx_header_size = 0;	// No effect for IT context.

-		max_ctx_payload_size = amdtp_stream_get_max_payload(s);

 		if (!(s->flags & CIP_NO_HEADER))

 			max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;

 	}