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

[Takashi Sakamoto]

On Aug 12 2014 16:09, Clemens Ladisch wrote:
> Takashi Sakamoto wrote:
>> On Aug 11 2014 00:54, Clemens Ladisch wrote:
>>> 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.
>> [...]
>> 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.
> 
> Apparently, the firmware doesn't support automatic format detection
> completely, and requires this command for the 2ch 32/44.1 kHz modes.

Apparently and completely, why? Please tell show reasons to judge about
a lack of automatic format detection. When you developed and committed
firewire-speakers driver, you confirmed all of combination for PCM
rate/channels, didn't you?

> (That 2ch at 96 kHz actually works is even more curious.  There already
> is that bug regarding listing the seventh format; it's possible that
> they completely forgot to report an eighth format.)

According to Griffin's manual for FireWave, 2ch/96kHz is not supported.
http://griffintechnology.com/support/firewave

> 32kHz, 44.1kHz, 48kHz and 96kHz playback in MBLA mode (non-Dolby)
> 32kHz, 44.1kHz, 48kHz in Dolby Pro Logic II
> 48kHz Encoded Digital in Dolby Digital

So it's natural that there is not the eight format. I think we're not
need to consider 2ch/96kHz mode.

Instead, we should consider the 2ch modes. This mode seems to be used
for Dolby Pro Logic II and Dolby Digital but I don't know about the
specification of Dolby something. If we drop these modes, the work to
develop OXFW driver becomes simpler.


Regards

Takashi Sakamoto
o-takashi at sakamocchi.jp