jwatte
Posts: 203
Joined: Sat Aug 13, 2011 7:28 pm

Getting Teensy 3.2 USB Audio working

Tue Aug 08, 2017 11:12 pm

I'm hooking a Teensy 3.2 board up to a Raspberry Pi 2 B. I'm using Raspbian updated last month. (debian_version says 8.0, uname -a says Linux robot-raspberrypi 4.9.35-v7+ #1014 SMP Fri Jun 30 14:47:43 BST 2017 armv7l GNU/Linux)

I am building an "Audio" sketch for the Teensy, which makes it appear as a USB audio output device. (Also: A MIDI and a serial port endpoint)

Unfortunately, the Audio device endpoint doesn't work with the snd_usb_audio module, it fails with a mysterious error -16. Google is very little help here.

Here's the output from dmesg when plugging it in:

Code: Select all

[10393.475126] usb 1-1.5: new full-speed USB device number 107 using dwc_otg
[10393.608837] usb 1-1.5: New USB device found, idVendor=16c0, idProduct=048a
[10393.608858] usb 1-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[10393.608868] usb 1-1.5: Product: Teensy MIDI/Audio
[10393.608879] usb 1-1.5: Manufacturer: Teensyduino
[10393.608889] usb 1-1.5: SerialNumber: 605160
[10393.610928] cdc_acm 1-1.5:1.0: ttyACM0: USB ACM device
[10393.612937] snd-usb-audio 1-1.5:1.2: cannot find the slot for index 0 (range 0-0), error: -16
[10393.612955] usb 1-1.5: cannot create card instance 0
[10393.612988] snd-usb-audio: probe of 1-1.5:1.2 failed with error -16
[10393.613708] snd-usb-audio 1-1.5:1.3: cannot find the slot for index 0 (range 0-0), error: -16
[10393.613721] usb 1-1.5: cannot create card instance 0
[10393.613745] snd-usb-audio: probe of 1-1.5:1.3 failed with error -16
Here's the output of lsusb -v for this particular device:

Code: Select all

[email protected]:~/Arduino/audio_playout_sketch $ sudo lsusb -v

Bus 001 Device 108: ID 16c0:048a Van Ooijen Technische Informatica 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.01
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x16c0 Van Ooijen Technische Informatica
  idProduct          0x048a 
  bcdDevice            2.00
  iManufacturer           1 Teensyduino
  iProduct                2 Teensy MIDI/Audio
  iSerial                 3 605160
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          341
    bNumInterfaces          6
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xc0
      Self Powered
    MaxPower              100mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          2 Communications
      bFunctionSubClass       2 Abstract (modem)
      bFunctionProtocol       1 AT-commands (v.25ter)
      iFunction               4 (error)
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         2 Communications
      bInterfaceSubClass      2 Abstract (modem)
      bInterfaceProtocol      1 AT-commands (v.25ter)
      iInterface              0 
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x01
          call management
        bDataInterface          1
      CDC ACM:
        bmCapabilities       0x06
          sends break
          line coding and serial state
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval              64
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      3 MIDI Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      MIDIStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength           65
      MIDIStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (MIDI_IN_JACK)
        bJackType               1 Embedded
        bJackID                 1
        iJack                   0 
      MIDIStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (MIDI_IN_JACK)
        bJackType               2 External
        bJackID                 2
        iJack                   0 
      MIDIStreaming Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (MIDI_OUT_JACK)
        bJackType               1 Embedded
        bJackID                 3
        bNrInputPins            1
        baSourceID( 0)          2
        BaSourcePin( 0)         1
        iJack                   0 
      MIDIStreaming Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (MIDI_OUT_JACK)
        bJackType               2 External
        bJackID                 4
        bNrInputPins            1
        baSourceID( 0)          1
        BaSourcePin( 0)         1
        iJack                   0 
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x05  EP 5 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
        bRefresh                0
        bSynchAddress           0
        MIDIStreaming Endpoint Descriptor:
          bLength                 5
          bDescriptorType        37
          bDescriptorSubtype      1 (GENERAL)
          bNumEmbMIDIJack         1
          baAssocJackID( 0)       1
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
        bRefresh                0
        bSynchAddress           0
        MIDIStreaming Endpoint Descriptor:
          bLength                 5
          bDescriptorType        37
          bDescriptorSubtype      1 (GENERAL)
          bNumEmbMIDIJack         1
          baAssocJackID( 0)       3
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         3
      bInterfaceCount         3
      bFunctionClass          1 Audio
      bFunctionSubClass       1 Control Device
      bFunctionProtocol       0 
      iFunction               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              0 
      AudioControl Interface Descriptor:
        bLength                10
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength           62
        bInCollection           2
        baInterfaceNr( 0)       4
        baInterfaceNr( 1)       5
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0602 Digital Audio Interface
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               1
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                10
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                49
        bSourceID               3
        bControlSize            1
        bmaControls( 0)      0x01
          Mute Control
        bmaControls( 1)      0x02
          Volume Control
        bmaControls( 2)      0x02
          Volume Control
        iFeature                0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             4
        wTerminalType      0x0602 Digital Audio Interface
        bAssocTerminal          0
        bSourceID              49
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        4
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        4
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bDelay                  3 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            1 Discrete
        tSamFreq[ 0]        44100
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x86  EP 6 IN
        bmAttributes            9
          Transfer Type            Isochronous
          Synch Type               Adaptive
          Usage Type               Data
        wMaxPacketSize     0x00b4  1x 180 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        5
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        5
      bAlternateSetting       1
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           3
        bDelay                  3 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            1 Discrete
        tSamFreq[ 0]        44100
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x07  EP 7 OUT
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x00b4  1x 180 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress         136
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x88  EP 8 IN
        bmAttributes           17
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0003  1x 3 bytes
        bInterval               1
        bRefresh                5
        bSynchAddress           0
Device Status:     0x0000
  (Bus Powered)

How can I get this audio device recognized?

jwatte
Posts: 203
Joined: Sat Aug 13, 2011 7:28 pm

Re: Getting Teensy 3.2 USB Audio working

Thu Aug 10, 2017 11:45 pm

Code: Select all

snd-usb-audio 1-1.5:1.2: cannot find the slot for index 0 (range 0-0), error: -16
The answer is that the USB audio module wants sound card slot 0 for the first USB audio device, but that slot is already taken by the BCM host audio.
The fix is to create a new file such as /etc/modprobe.d/snd_usb_audio.conf, and put a new index into it:

Code: Select all

options snd_usb_audio index=1
A number of tutorials and resources on the web suggest that there's an alsa-specific config file in modprobe.d where this line could go, but on modern systems, no such file exists (alsa configs have moved into /usr/share/alsa)

Return to “Troubleshooting”