[alsa-devel] USB asynchronous mode feedback format

[Julian Scheel]

Am Freitag, 15. Oktober 2010, 14:52:15 schrieb Alex Lee:
> > So my data is (48<<13):
> >     char data[4];
> >     data[0] = 0x00;
> >     data[1] = 0x06;
> >     data[2] = 0x00;
> >     data[3] = 0x00;
> >     
> >     AUDDSpeakerDriver_WriteFeedback(data, 4,
> >     
> >                     (TransferCallback)FeedbackSent,
> >                     NULL);
> > 
> > Whenever the feedback was sent (ie it was queried by the host), this
> > method is called again and it sends the feedback again.
> > Is this ok in general or is there some basic problem with this feedback
> > style?
> 
> UAC data should be Big Endian.  Send the LSB byte first.

Ah right, thanks.
Well now I swapped data[1] and data[2]. When monitoring the amount of data I 
get per read, it is constant at 192bytes, which would be expected for feedback 
ratio of 48, right? But if I have 0x06 to 0x07 for example I do still get 
exactly 192bytes per read, shouldn't I get less data in that case? (I always 
try to read up to MAXPACKETSIZE which is 512, btw)

Regards,
Julian