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Date:      Sun, 8 Oct 2017 13:19:19 +0200
From:      Hans Petter Selasky <hps@selasky.org>
To:        Alexander Leidinger <Alexander@leidinger.net>, "freebsd-usb@FreeBSD.org" <freebsd-usb@FreeBSD.org>
Subject:   Re: uaudio - distorted output
Message-ID:  <633f23dd-3b61-fe17-b894-6b1221a5dfd4@selasky.org>
In-Reply-To: <20171008125631.Horde.ZsqSFDr1-uiT1YrkgH5i0tF@webmail.leidinger.net>
References:  <20171008125631.Horde.ZsqSFDr1-uiT1YrkgH5i0tF@webmail.leidinger.net>

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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?

Try to enable hw.usb.uaudio.debug=16 during playback.

--HPS



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