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ALSA: firewire-motu: fix truncated bytes in message tracepoints

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In MOTU protocol v2/v3, first two data chunks across 2nd and 3rd data
channels includes message bytes from device. The total size of message
is 48 bits per data block.

The 'data_block_message' tracepoints event produced by ALSA firewire-motu
driver exposes the sequence of messages to userspace in 64 bit storage,
however lower 32 bits are actually available since current implementation
truncates 16 bits in upper of the message as a result of bit shift
operation within 32 bit storage.

This commit fixes the bug by perform the bit shift in 64 bit storage.

Fixes: c6b0b9e65f ("ALSA: firewire-motu: add tracepoints for messages for unique protocol")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210920110734.27161-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2021-09-20 20:07:34 +09:00 committed by Takashi Iwai
parent 77ff9e7be0
commit cb1bcf5ed5
1 changed files with 4 additions and 3 deletions
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7
sound/firewire/motu/amdtp-motu.c
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@ -276,10 +276,11 @@ static void __maybe_unused copy_message(u64 *frames, __be32 *buffer,
/* This is just for v2/v3 protocol. */
for (i = 0; i < data_blocks; ++i) {
*frames = (be32_to_cpu(buffer[1]) << 16) |
(be32_to_cpu(buffer[2]) >> 16);
*frames = be32_to_cpu(buffer[1]);
*frames <<= 16;
*frames |= be32_to_cpu(buffer[2]) >> 16;
++frames;
buffer += data_block_quadlets;
frames++;
}
}