Date: Fri, 9 Feb 2018 16:12:31 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Ert Retre <ailinaini@yahoo.com>, "freebsd-usb@freebsd.org" <freebsd-usb@freebsd.org> Subject: Re: uaudio - distorted output Message-ID: <56fad69d-faf9-cfd5-6b81-31594c9d248b@selasky.org> In-Reply-To: <975281149.1691406.1518176869272@mail.yahoo.com> References: <975281149.1691406.1518176869272.ref@mail.yahoo.com> <975281149.1691406.1518176869272@mail.yahoo.com>
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On 02/09/18 12:47, Ert Retre via freebsd-usb 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. Hi, If your device is FULL speed, you cannot connect it via an external HUB for more than 2 channels, recording and playback simultaneously. There is a capacity issue (except when using XHCI) and it will cause clipping. Can you send the full output from usbconfig? --HPS
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