Re: Controlling the Tascam FW-1884

[Scott Bahling <sbahling@suse.com>]

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Hi Takashi,

On Mon, 2018-09-10 at 16:59 +0900, Takashi Sakamoto wrote:

<snip>

> As long as I know, the image consists of below information:
>   - pos  0-15: control messages from physical control surface
>   - pos 16-23: analog input level
>   - pos 24-31: digital ADAT input level
>   - pos 32-33: digital S/PDIF input level
>   - pos 34-35: (not cleared yet)
>   - pos 36-43: analog output level
>   - pos 44-64: (not cleared yet)
> 
> When parsing the image, a parser should generate several types of
> events. I prefer to implementing this complicated work in user space
> instead of kernel space. Expecially for pos 16-23/24-31/32-33/36-43, the
> parser should always generate events to notify each of the levels.
> 
> What we should do is to parsing the image and generate events with
> enough consideration of task scheduling and eventing dencity. The parser
> could be implemented as an application of ALSA sequencer.

Thanks for the details. I can work on deciphering the raw control messages.
My current idea is to set up a netlink socket and stream the control data to
user space just for analysis. I will look into ALSA sequencer to see if I
can understand how that could be used.

I noticed that we are able to control the LEDs from the host via the
asynchronous link. Do you you think the faders are also controlled that way
or would that also go via isochronous packets to the FW-1884?

Regards,

Scott

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