Is there a place to discuss likely-cheap USB MIDI devices?

[sdstrowes]

Is there a place to discuss likely-cheap USB MIDI devices? Because what I have lying around is a "mio iConnectivity" MIDI to USB adapter.

It does work: if I run munt on top of a full raspbian install on my rpi3, it plays without issue. So I know the hardware is good, but I don't know what the gap is between that and mt32-pi (current release, 0.8.3).

In case it offers any insight, the device info from dmesg and lsusb is pasted below. If there's scope to make this work, I'd be happy to try to debug further. If it's a lost cause and not worth the effort, I'll just buy something good to replace this!

[  102.518031] usb 1-1.2: new full-speed USB device number 12 using dwc_otg
[  102.658396] usb 1-1.2: New USB device found, idVendor=2321, idProduct=000a, bcdDevice= 1.00
[  102.658417] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  102.658431] usb 1-1.2: Product: mio
[  102.658445] usb 1-1.2: Manufacturer: iConnectivity
[  102.658458] usb 1-1.2: SerialNumber: 00018CD5

Bus 001 Device 012: ID 2321:000a  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x2321 
  idProduct          0x000a 
  bcdDevice            1.00
  iManufacturer           1 iConnectivity
  iProduct                2 mio
  iSerial                 3 00018CD5
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0065
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower               40mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength       0x0009
        bInCollection           1
        baInterfaceNr(0)        1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      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       0x0041
      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     0x81  EP 1 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
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               0
        bRefresh                0
        bSynchAddress           0
        MIDIStreaming Endpoint Descriptor:
          bLength                 5
          bDescriptorType        37
          bDescriptorSubtype      1 (GENERAL)
          bNumEmbMIDIJack         1
          baAssocJackID( 0)       1
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0000
  (Bus Powered)

[dwhinham]

Hi there - discussing it here is fine. 🙂

Your interface seems to be decent quality, the manufacturer has a website and the device gets good reviews, so it should be good for these purposes. When we refer to "cheap" USB MIDI devices, it's mainly the nameless ones you find on eBay for less than $5 that are completely broken no matter what system you use it with.

The descriptors for this device look standard and class-compliant, so it should work in theory.

Just some sanity-checks:

• Are you connecting the device before turning on the Pi and booting mt32-pi? mt32-pi does not currently support hot-plug, so if the USB device is not present at startup, it won't work.
• Is usb = on in the config file?

I've attached an HDMI-enabled build here:
kernel8.zip

Could you attach a display to the Pi and run this? Maybe the logs can offer some clues.
Thanks!

[sdstrowes]

Yes, the USB-MIDI device is connected on boot, and usb = on in the config.

Thanks for throwing me an HDMI-enabled kernel; I was getting ready to build! Here's the output: https://imgur.com/6S362m5

[dwhinham]

Thanks for the output - it looks like the device is just not being detected at all.

I've done some testing myself with my Pi 3 B+ and found something strange - my M-AUDIO USB Uno is not detected at all if I plug it into the USB ports closest to the GPIO header, but my Roland UM-ONE works fine there.

But if I move the Uno to one of the ports closest to the Ethernet port, it gets detected.

Could you try moving the device to different ports and see if the log output changes?

For reference, a "good" log looks like this:

[dwhinham]

I've done some more testing and discovered two possible issues with Circle's USB drivers:

• Some USB MIDI devices seem to not work on certain ports when not using the Plug & Play features (current release of mt32-pi does not).
• On Pi 3 A+ (which only has one USB port, no hub), with PnP enabled, hot-plugging some MIDI devices at runtime causes a hard freeze. If the device is present at startup, it seems to work fine.

I wanted to enable USB hotplug anyway (issue #36), so I've done so, and that seems to get my Uno working in the other ports. I have a feeling it may get your device working too.

Could you try this build and report back? https://github.com/dwhinham/mt32-pi/actions/runs/492490592
Just download the kernels "artifact" from the page - also, it's a release build and doesn't have HDMI support.

Meanwhile I'll prepare some bug reports for upstream.
Thanks!

[sdstrowes]

So I had no luck switching between all four USB ports on the prior build (I actually tried this last night, but with no luck I didn't think it might ever be significant).

But the latter build you put together just worked first time for me. That's super nice; thank you so much!

[dwhinham]

Excellent!

I have one more test for you to try. Could you go back to the latest release version, and add usbpowerdelay=2000 to the first line of your cmdline.txt?

That should make it read fast=true usbpowerdelay=2000.

This should hopefully get your device working on the release version and hopefully takes care of the first problem above.

[sdstrowes]

Ah, yes, 0.8.3 with usbpowerdelay=2000 also works (on any USB port)!

[dwhinham]

Great, thanks for reporting back 🙂

I'll document this possible fix in the wiki and will probably release a new version with the PnP support shortly.

---

Edit: wiki page updated with your USB interface and info about the power delay: https://github.com/dwhinham/mt32-pi/wiki/USB-MIDI-interfaces

[sdstrowes]

Awesome. Thanks again for the help!