From f937b43d48f1080e39de723d15680b2ad5d7e6fd Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Tue, 20 Oct 2015 23:46:59 +0900
Subject: [PATCH] ALSA: firewire-tascam: clear extra MIDI bytes in an
asynchronous transaction
When MIDI buffer stores two or more MIDI messages, TASCAM driver
transfers asynchronous transactions including one MIDI message and
extra bytes from second MIDI message.
This commit fixes this bug by clearing needless bytes in the buffer. The
consumed bytes are already calculated correctly, thus the sequence of
transactions is already correct.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/firewire/tascam/tascam-transaction.c | 24 ++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c
index 99098aa2391e4..904ce0329fa1a 100644
--- a/sound/firewire/tascam/tascam-transaction.c
+++ b/sound/firewire/tascam/tascam-transaction.c
@@ -93,8 +93,10 @@ static int fill_message(struct snd_rawmidi_substream *substream, u8 *buf)
*label = (port << 4) | 0x04;
/* We need to fill whole 3 bytes. Go to next change. */
} else {
- consume = 0;
+ return 0;
}
+
+ len = consume;
} else {
/* The beginning of exclusives. */
if (msg[0] == 0xf0) {
@@ -115,24 +117,30 @@ static int fill_message(struct snd_rawmidi_substream *substream, u8 *buf)
/* On running-status. */
if ((msg[0] & 0x80) != 0x80) {
+ /* Enough MIDI bytes were not retrieved. */
+ if (consume < len - 1)
+ return 0;
+ consume = len - 1;
+
msg[2] = msg[1];
msg[1] = msg[0];
msg[0] = tscm->running_status[port];
- consume--;
} else {
+ /* Enough MIDI bytes were not retrieved. */
+ if (consume < len)
+ return 0;
+ consume = len;
+
tscm->running_status[port] = msg[0];
}
-
- /* Confirm length. */
- if (consume < len)
- return 0;
- if (consume > len)
- consume = len;
}
*label = (port << 4) | (msg[0] >> 4);
}
+ if (len > 0 && len < 3)
+ memset(msg + len, 0, 3 - len);
+
return consume;
}