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I have a USB MIDI cable which shows up on connect in the kernel messages as:

usb 1-1.2: new full-speed USB device number 12 using dwc_otg

yet, somehow in lsusb this device does not show up:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.

pmidi -l also only results in this:

Port     Client name                       Port name
14:0     Midi Through                      Midi Through Port-0

I've tried a powered USB hub since this is connected to a Raspberry Pi, but it made no difference. The device shows up correctly on a Mac computer, though.

It is the following model:

USB_ID(0x1a86, 0x752d): /* QinHeng CH345 "USB2.0-MIDI" */

I am not sure how to further debug this problem. Are there any feasible ways to see what is going on (with Alsa maybe?) when connecting the interface?

update

I didn't realise that this Raspberry Pi is running Debian, not Ubuntu, so this might be off-topic here. Still, I would appreciate if someone has a general approach to dealing with this kind of problem.

update

/var/log/syslog is more specific. on disconnecting the device (and reconnecting) i get this sequence of messages:

Jan  2 14:32:09 raspberrypi kernel: [  657.661712] usb 1-1.2.3: new full-speed USB device number 5 using dwc_otg
Jan  2 14:32:09 raspberrypi kernel: [  657.741724] usb 1-1.2.3: device descriptor read/64, error -32
Jan  2 14:32:09 raspberrypi kernel: [  657.931743] usb 1-1.2.3: device descriptor read/64, error -32
Jan  2 14:32:09 raspberrypi kernel: [  658.121670] usb 1-1.2.3: new full-speed USB device number 6 using dwc_otg
Jan  2 14:32:09 raspberrypi kernel: [  658.201652] usb 1-1.2.3: device descriptor read/64, error -32
Jan  2 14:32:09 raspberrypi kernel: [  658.391681] usb 1-1.2.3: device descriptor read/64, error -32
Jan  2 14:32:10 raspberrypi kernel: [  658.581705] usb 1-1.2.3: new full-speed USB device number 7 using dwc_otg
Jan  2 14:32:10 raspberrypi kernel: [  659.001374] usb 1-1.2.3: device not accepting address 7, error -32
Jan  2 14:32:10 raspberrypi kernel: [  659.081777] usb 1-1.2.3: new full-speed USB device number 8 using dwc_otg
Jan  2 14:32:10 raspberrypi kernel: [  659.501382] usb 1-1.2.3: device not accepting address 8, error -32
Jan  2 14:32:10 raspberrypi kernel: [  659.501806] hub 1-1.2:1.0: unable to enumerate USB device on port 3

this was on a powered usb hub. same result when connecting directly.

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What kind of MIDI cable is that? I can't find any details about it on Google. –  Rafał Cieślak Jan 4 '13 at 17:05
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1 Answer 1

These "descriptor read" and "address" errors indicate that the USB communication with the device does not work for some reason.

It's likely that the cable, a connector, the host controller, or the device is defective.

Try with another controller/cable/device to check which one.

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