Raspberry PI 2B/3 and USB audio

[Hans Petter Selasky]

On 11/28/18 11:13 AM, Brian Scott wrote:
> On 28/11/18 7:45 pm, Hans Petter Selasky wrote:
>> On 11/28/18 1:46 AM, Brian Scott wrote:
>>> On 27/11/18 6:38 pm, Hans Petter Selasky wrote:
>>>> On 11/26/18 8:47 PM, Herbert J. Skuhra wrote:
>>>>> Well, this USB sound card works perfectly fine on my desktop PC
>>>>> running FreeBSD (amd64).
>>>>
>>>> Hi,
>>>>
>>>> There is a problem in the DWC OTG USB controller driver that it cannot
>>>> handle the big data payload 24-bit 48KHz sampling requires.
>>>> Unfortunately your device has only one sample size selection.
>>>>
>>>> If you buy a USB sound device marked as "HIGH SPEED USB" it should
>>>> work. Yours is "spd=FULL".
>>>>
>>>> --HPS
>>> Just an additional data point,
>>>
>>> This one also sounds like junk but is high speed:
>>>
>>>       ugen0.6: <Generic USB Audio> at usbus0, cfg=0 md=HOST spd=HIGH
>>>       (480Mbps) pwr=ON (100mA)
>>>
>>>         bLength = 0x0012
>>>         bDescriptorType = 0x0001
>>>         bcdUSB = 0x0200
>>>         bDeviceClass = 0x0000  <Probed by interface class>
>>>         bDeviceSubClass = 0x0000
>>>         bDeviceProtocol = 0x0000
>>>         bMaxPacketSize0 = 0x0040
>>>         idVendor = 0x0bda
>>>         idProduct = 0x4040
>>>         bcdDevice = 0x0000
>>>         iManufacturer = 0x0003  <Generic>
>>>         iProduct = 0x0001  <USB Audio>
>>>         iSerialNumber = 0x0002  <201405280001>
>>>         bNumConfigurations = 0x0001
>>>
>>> But I notice that it handles both 48000 and 8000 according to the sound
>>> driver.
>>>
>>>       cat /dev/sndstat
>>>       FreeBSD Audio Driver (64bit 2009061500/aarch64)
>>>       Installed devices:
>>>       pcm0: <USB audio> at ? kld snd_uaudio (1p:1v/1r:1v) default
>>>           snddev flags=0x2e2<AUTOVCHAN,BUSY,MPSAFE,REGISTERED,VPC>
>>>           [pcm0:play:dsp0.p0]: spd 48000, fmt 0x00200010, flags
>>>       0x00002100, 0x00000004
>>>           interrupts 0, underruns 0, feed 0, ready 0
>>>       [b:3072/1536/2|bs:4096/2048/2]
>>>           channel flags=0x2100<BUSY,HAS_VCHAN>
>>>           {userland} -> feeder_mixer(0x00200010) -> {hardware}
>>>           pcm0:play:dsp0.p0[pcm0:virtual:dsp0.vp0]: spd 8000, fmt
>>>       0x00100008, flags 0x10000000, 0x00000000
>>>           interrupts 0, underruns 0, feed 0, ready 0 [b:0/0/0|bs:0/0/0]
>>>           channel flags=0x10000000<VIRTUAL>
>>>           {userland} -> feeder_root(0x00000000) -> {hardware}
>>>           [pcm0:record:dsp0.r0]: spd 48000,fmt 0x00200010/0x00210000,
>>>       flags 0x00002100, 0x00000007
>>>           interrupts 0, overruns 0, feed 0, hfree 4608, sfree 4096
>>>       [b:4608/2304/2|bs:4096/2048/2]
>>>           channel flags=0x2100<BUSY,HAS_VCHAN>
>>>           {hardware} -> feeder_root(0x00210000) ->
>>>       feeder_format(0x00210000 -> 0x00200010) -> feeder_mixer(0x00200010)
>>>       -> {userland}
>>>           pcm0:record:dsp0.r0[pcm0:virtual:dsp0.vr0]: spd 8000, fmt
>>>       0x00100008, flags 0x10000000, 0x00000000
>>>           interrupts 0, overruns 0, feed 0, hfree 0, sfree 0
>>>       [b:0/0/0|bs:0/0/0]
>>>           channel flags=0x10000000<VIRTUAL>
>>>           {hardware} -> feeder_root(0x00000000) -> {userland}
>>>       No devices installed from userspace.
>>>
>>> Output sounds like rubbish with both 8000 speed stuff sent directly to
>>> /dev/dsp using cat and higher quality stuff sent via sox play.
>>>
>>> It could also just be a junk piece of hardware from my local electronics
>>> shop.
>>
>> Which version of FreeBSD is this?
>>
>> Can you show dmesg?
>>
>> --HPS
>>
> 12.0 RC2 with /boot and /boot/msdos on sdcard and everything else on USB
> connected hard drive (causing interference with the bus?). Otherwise
> everything directly off the RC2 image + packages and a bit of configuration.
> 
> On repeating my tests (probably last done a few months ago with the
> current snapshot) the sound was much better than I remember (almost
> recognisable!). Maybe having the non-debug kernel is helping. Hope this
> isn't a red herring.
> 

Can you set the:

sysctl dev.pcm.0.play.vchanrate=48000
sysctl dev.pcm.0.rec.vchanrate=48000

And try again?

--HPS