USB Audio on FreeBSD 5.2.1-release?

Mathew Kanner mat at
Fri Sep 24 14:35:27 PDT 2004

On Sep 24, Torfinn Ingolfsen wrote:
> Hei,
> Are USB audio devices suposed to work without problems under FreeBSD
> 5.2.1-release?
> I have a USB Speaker set, when connected to the machine, it is identifed
> as:
> # usbdevs -v
> Controller /dev/usb0:
> addr 1: full speed, self powered, config 1, OHCI root hub(0x0000),
>             SiS(0x0000), rev 1.00
>  port 2 addr 3:full speed, power 500 mA, config 1, USB Audio(0x0001),
>                      C-Media INC.(0x0d8c), rev 0.10
> It attaches as (from /var/log/messages):
> Sep 24 17:02:31 kg-work kernel: uaudio0: audio rev 1.00
> Sep 24 17:02:31 kg-work kernel: pcm1: <USB Audio> on uaudio0
> However, when i try to play a MP3 file (using XMMS) it sounds stuttering
> or "choppy" if you know what I mean.
> The same MP3 file sounds fine when played on the internal sound device.

	There are some tests you can try out.  Use mplayer to play
mp3s and force the output to 48khz 
	There are problems with USB audio.  Could you try

	Something that I was working on a couple of weeks ago.  You
	sysctl hw.usb.uadion.delay=0

	You'll loose the mixer but it should report the speed a little
better and I think they (netbsd) improved the packet size calculation.
It also picks up the endpoints better (iirc).


	Canada is a country whose main exports are hockey players
	and cold fronts. Our main imports are baseball players and
	acid rain.
			- Pierre Elliott Trudeau

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