Re: [RFC][PATCH 00/15 v4] OXFW driver, a succesor to firewire-speakers

[Takashi Sakamoto <o-takashi@sakamocchi.jp>]

On Aug 11 2014 00:54, Clemens Ladisch wrote:
> Takashi Sakamoto wrote:
>> I have an issue for Griffin Firewave.
>>
>> This device can handle AV/C Stream Format Information command and
>> driver can get to know stream formations via the command.
>>
>> According to these responses, supported formations are:
>> Input Stream to device:
>> 	Rate	PCM	MIDI
>> 	32000	6	0
>> 	44100	6	0
>> 	48000	6	0
>> 	96000	6	0
>> 	32000	2	0
>> 	44100	2	0
>> 	48000	2	0
>>
>> But current 'firewire-speakers' has PCM constraints below:
>>  - 6ch at 32/44.1/48/96 kHz
>>  - 2ch at 48/96 kHz
>> http://mailman.alsa-project.org/pipermail/alsa-devel/2014-February/073562.html
>>
>> So this OXFW driver may lost a support for 2ch/96.0kHz for FireWave
>> and gain 2ch/32.0kHz and 2ch/44.1kHz.
>>
>> I don't know exactly the reason of these gaps.
> 
> The old driver configured nothing but the rate.  Is there any mechanism
> to set the stream format?

Yes. It's AV/C stream format information command.

The old driver uses AV/C plug signal format command. This command
basically get/set sampling rate.

But the stream format information command can be available to get/set
stream format and some models with OXFW, especially FireWave, uses this
command.

But in this series of patches, I don't use this command. I expected the
models to change stream format according to parameters in AMDTP packets
such like the value of dbs field.


Regards

Takashi Sakamoto
(In summer vacation)
o-takashi@sakamocchi.jp


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