[alsa-devel] [PATCH v2] ALSA: firewire-lib/fireworks: fix miss detection of received MIDI messages

[Takashi Iwai]

On Mon, 01 Jul 2019 16:43:53 +0200,
Takashi Sakamoto wrote:
> 
> In IEC 61883-6, 8 MIDI data streams are multiplexed into single
> MIDI conformant data channel. The index of stream is calculated by
> modulo 8 of the value of data block counter.
> 
> In fireworks, the value of data block counter in CIP header has a quirk
> with firmware version v5.0.0, v5.7.3 and v5.8.0. This brings ALSA
> IEC 61883-1/6 packet streaming engine to miss detection of MIDI
> messages.
> 
> This commit fixes the miss detection to modify the value of data block
> counter for the modulo calculation.
> 
> For maintainers, this bug exists since a commit 18f5ed365d3f ("ALSA:
> fireworks/firewire-lib: add support for recent firmware quirk") in Linux
> kernel v4.2. There're many changes since the commit.  This fix can be
> backported to Linux kernel v4.4 or later. I tagged a base commit to the
> backport for your convenience.
> 
> Besides, my work for Linux kernel v5.3 brings heavy code refactoring and
> some structure members are renamed in 'sound/firewire/amdtp-stream.h'.
> The content of this patch brings conflict when merging -rc tree with
> this patch and the latest tree. I request maintainers to solve the
> conflict to replace 'tx_first_dbc' with 'ctx_data.tx.first_dbc'.
> 
> Fixes: df075feefbd3 ("ALSA: firewire-lib: complete AM824 data block processing layer")
> Cc: <stable at vger.kernel.org> # v4.4+
> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>

Applied now.  Thanks.


Takashi