Subject: Re: 6ch playing with USB audio
To: None <tech-kern@netbsd.org>
From: TAMURA Kent <kent@netbsd.org>
List: tech-kern
Date: 03/21/2002 19:06:05
> > -#define UAUDIO_NFRAMES   20    /* ms of sound in each request */
> > +#define UAUDIO_NFRAMES   10    /* ms of sound in each request */
Ignatios Souvatzis writes:
> isn't this run-time settable using the audioctl blocksize parameter

No.  It seems uaudio always transfers bytes_per_frames *
UAUDIO_NFRAMES byte data at one USB request regardless of
blocksize.

Jaromir writes:
> Do you have an idea why it helps? Does the code overload
> the bus with bursty big transfers, or are the USB transfers
> too big in the 44.1KHz 6ch 16bit sound case? IIRC the code
> did only couple byte USB transfers for low-quality sound
> (like 8Kbit mono).

I think the change decreases the size of data for one call of
usbd_transfer() and increases the number of times of
usbd_transfer() in 1 second.

-- 
TAMURA Kent <kent2002@hauN.org> <kent@netbsd.org>