Re: [alsa-devel] Github MOTU PCI 324; Motu 2408; Motu 1224

Re: [alsa-devel] Github MOTU PCI 324; Motu 2408; Motu 1224

[Takashi Sakamoto]

Hi Yan,
(CCed to alsa-devel)

On Tue, Jan 14, 2020, at 02:07, Yannic Korten wrote:
> Hey Mr. Takashi,
> I'm new to Linux and new to Github. If you think this is spam or you 
> wanted to be in private: See this mail as spam - ignore and just delete 
> it. I'm sorry then.
> But I have a problem and don't know whom to contact. It seems like you 
> have much experience with coding and the usage of ALSA (which seems to 
> be your project).
> So, my setup is the following:
> Ubuntu Studio 19.10
> MOTU 324 PCI Card (detected as 'Multimedia audio controller: Mark of 
> the Unicorn Inc PCI-324 Audiowire Interface (rev 0a)')
> MOTU 1224
> MOTU 2408
> So I tried to install your files from github but it seems not to be 
> working. Either it's because it's just the support for some newer MOTU 
> devices or I'm to dumb.
> Is it possible to get the above devices fully running on linux with 
> your "drivers"? Or are they not supporting?
> Will it be possible to insert them to the code (easily)? Or is it way 
> to much expenditure for that old devices?
> 
> Thanks for help
> Greetings from Germany
>  Yan

I'm an author/maintainer of ALSA firewire stack which includes snd-firewire-motu
driver. The driver can handle MOTU's FireWire series for IEEE 1394 bus; e.g.
MOTU 828mkII. Unfortunately, the driver is unavailable for your model.

Your model is not compliant to IEEE 1394. It's for 'AudioWire', which is proprietary
protocol developed by MOTU. Like 1394 OHCI card is for IEEE 1394 bus,
PCI-324/424 ASIC card is for 'AudioWire'. The ASIC is designed by MOTU itself
(Precisely S&S Research, Inc.) and the detail is closed.

Although PCI-324/424 card has physical ports into which IEEE 1394 cables can
connect, and actually AudioWire uses the same cable of IEEE 1394a, signals in the
cable is completely different from IEEE 1394. In the summer of 2015, I bought
AudioWire-based model (it's really cheep in used market) and attempted to
connect it to my IEEE 1394 bus analyzer. As I expected, nothing can be detected.

I guess that PCI-324/424 ASIC integrates a sort of computing core (e.g. ARM7TDMI)
with PCI interface for AudioWire protocol. For this kind of device, people need to
work for reverse-engineering by analyze MOTU driver's behaviour in memory space
mapped to host system, and write new driver to emulate the behaviour.

However, this is a kind of 'adventure' and no guarantee to achieve. On the other hand,
it certainly consumes the batch of developer's resources, unless getting enough
assists by vendors. This is a reason that you cannot see AudioWire compliant drivers
as Open Source Software.


Regards

Takashi Sakamoto
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