uaudio - distorted output

[Hans Petter Selasky]

On 10/09/17 21:05, Alexander Leidinger wrote:
> Quoting Hans Petter Selasky <hps at selasky.org> (from Sun, 8 Oct 2017 
> 23:44:27 +0200):
> 
>> Can you trace that with:
>>
>> usbdump -i usbusX -f Y -v
>>
>> ?
>>
>> What rates are supported. Can you try 48000 Hz?
> 
> 44100 and 48000. The attached usbdumps are with 48000 Hz. The "1" is 
> with 32bit audio output, the "2" with 16bit audio output.
> 
> This is what is reported in dmesg:
> ---snip---
> uaudio0 on uhub3
> uaudio0: <Creative Technology SB Live 24-bit External, class 0/0, rev 
> 1.10/1.00, addr 2> on usbus5
> uaudio0: Play: 48000 Hz, 4 ch, 24-bit S-LE PCM format, 2x8ms buffer.
> uaudio0: Play: 44100 Hz, 4 ch, 24-bit S-LE PCM format, 2x8ms buffer.
> uaudio0: Record: 96000 Hz, 2 ch, 24-bit S-LE PCM format, 2x8ms buffer.
> uaudio0: Record: 48000 Hz, 2 ch, 24-bit S-LE PCM format, 2x8ms buffer.
> uaudio0: Record: 44100 Hz, 2 ch, 24-bit S-LE PCM format, 2x8ms buffer.
> uaudio0: No MIDI sequencer.
> pcm2: <USB audio> on uaudio0
> uaudio0: No HID volume keys found.
> ---snip---
> 
> As this is a 5.1 device, I would expect 6 channels, not 4 (the config 
> descriptor dump is in my initial mail).
> 

Hi,

Is this device connected directly to the computer or via a USB HUB?

Can you show all USB devices on this computer?

I suspect your device is connected via USB High-speed HUB and I think 
the payload per millisecond is a bit too much for the so-called 
High-Speed to Full-Speed transaction translator configuration FreeBSD is 
using. You need to connect the device directly to an XHCI, UHCI or OHCI 
controller for it work properly.

The following define can be increased by 1, to get more bandwidth for 
periodic data, but will reduce the bandwidth for non-periodic data.

sys/dev/usb/usb_freebsd.h:#define	USB_FS_ISOC_UFRAME_MAX 4

If you are using multi channel audio equipment with 24-bits, try to 
avoid FULL-speed ones!

--HPS