[LAD] Details about Mackie Control or Mackie Human User Interface

Takashi Sakamoto o-takashi at sakamocchi.jp
Mon Jul 20 13:33:23 UTC 2015

Hi all,

I'm a ALSA developer. I currently focus on developing sound drivers for
devices on IEEE 1394 bus. In this developing period for Linux 4.3, I'm
working for TASCAM FireWire series such as FW-1884 and FW-1082.

Well, are there some developers who have enough knowledgement about MIDI
messaging rule for Mackie Control or Mackie Human User Interface(HUI)?

As long as investigating FW-1082 and FW-1884, these two models transfer
control messages over IEEE 1394 isochronous packets, The shape of these
messages is similar to bitmap. In detail, see my RFC on alsa-devel:

[alsa-devel] [RFC][PATCH 26/37] ALSA: firewire-tascam: add MMAP support
to show status and control message

To enable userspace applications to handle these messages, a converter
to MIDI messages is required, as Windows/OS X drivers did. In my
original plan, I off-load this task to userspace driver applications by
adding mmap(2)ed page. While, due to some reasons, it's better to
implement the converter into kernel driver.

As long as I know, for these models, there're three types of the
converter; usual MIDI messages such as Control Change (CC), Mackie
Control and Mackie Human User Interface, while I have a little
knowledgement about the latter two types.

For this occasion, I want to know the details. If a cost to implement
one of these two types, I'll use it for the converter. Else, I use usual
MIDI messages for my patchset to ALSA upstream.


Takashi Sakamoto

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