uaudio - distorted output

[Hans Petter Selasky]

On 10/08/17 14:25, Alexander Leidinger wrote:
> 
> Quoting Hans Petter Selasky <hps at selasky.org> (from Sun, 8 Oct 2017 
> 13:19:19 +0200):
> 
>> On 10/08/17 12:56, Alexander Leidinger wrote:
>>>
>>> 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?
> 
> current as of r323636
> 
>> Try to enable hw.usb.uaudio.debug=16 during playback.
> 
> No such sysctl, only hw.usb.debug....
> I did the hw.usb.debug=16, but no output in dmesg nor 
> /var/log/console.log nor /var/log/messages, where do I need to look?
> 
> Bye,
> Alexander.
> 

Can you compile and install snd_uaudio module with 
DEBUG_FLAGS="-DUSB_DEBUG" and KMODDIR=/boot/kernel ?

--HPS