uaudio - distorted output

[Ert Retre]

> Hi,
> 
> attached are the config descriptors and the device dump of two uaudio 
> devices. Both exhibit distorted audio output. It sounds a little bit 
> like clipping / not feeding enough samples fast enough...
> 
> I played around with dev.pcm.2.bitperfect=1, dev.pcm.2.play.vchans=0, 
> dev.pcm.2.play.vchanrate and hw.snd.latency=1...10.
> 
> At some point vchanrate doesn't work anymore, it always stays at 4.0 
> audio, even when trying to go back to 2.0. I have to usbconfig reset the 
> device.
> 
> Sometimes (rarely) when playing around I get clear audio output, but 
> when I try to reproduce it (going back to default value for the last 
> sysctl setting and then going back again to the same setting again), the 
> audio is distorted again.
> 
> To me it sounds like some kind of buffer is not big enough or the data 
> is not delivered fast enough to the uaudio device. But this is a 
> dual-socket system with:
>      CPU: Intel(R) Xeon(R) CPU           E5620  @ 2.40GHz (2133.36-MHz 
> K8-class CPU)
>      FreeBSD/SMP: Multiprocessor System Detected: 16 CPUs
>      FreeBSD/SMP: 2 package(s) x 4 core(s) x 2 hardware threads
> And while playing around with uaudio the system has a load of around 1, 
> so I would expect CPU/RAM is not an issue here.

Hi,

What version of FreeBSD is this?

Try to enable hw.usb.uaudio.debug=16 during playback.
--
Alexander Garcia
https://www.drillanddriver.com