need help w/logitech 350 usb headset on 5.3-Stable

Kazuhito HONDA kazuhito at
Sat Apr 23 22:32:50 PDT 2005


USB audio driver are suddenly improved 
by a few earnest developers, recently.
So it becomes useful, but it still has some problem.
Especially, a full duplex problem
--concerned with USB headset-- just start researching.
(It was described in arguments with Artem Ignatiev at this mailing-list.
But they have not uploaded in FreeBSD web page yet.)

You should check below:
1. You should use FreeBSD-stable or -current.
   You can't record with old FreeBSD.  kernels for recording is
       FreeBSD-4-stable after Apr 23
       FreeBSD-5-stable after Apr 16
       FreeBSD-current  after Apr 14.
   But there are fixes after that, you should use the latest codes.
   Released FreeBSDs don't have the codes for recording 
   and the latest fixes.

2. You had better know sampling rates of your headset.
   USB audio can't be used with a wrong sampling rate now.
   it is 48000 Hz in almost cases, and 44100 Hz sometime.

3. Is your USB controller ohci or uhci?
   uhci has no problem. But ohci has the full duplex problem.
   microphone and speaker can't be use simultaneously without full duplex.
   Then a USB headset can't be use with ohci.

   But if you want to use it as headphone only, or microphone only,
   ohci has no problem.

3'.If you want to use microphone and speaker simultaneously with uhci,
   you must comment-out below lines 
   at function uaudio_init_params() in uaudio.c

        if ((sc->sc_playchan.pipe != NULL) || (sc->sc_recchan.pipe != NULL))
                return (-1);

Kazuhito HONDA

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