Arch Linux

dkmb

Member

Registered: 2023-11-13

Posts: 1

Troubleshooting Web MIDI and udev device access

hello!

I am trying to get a web MIDI device to work, specifically, an expert sleepers fh-2, which is part of my modular synthesizer. it is programmed via a web MIDI page. other linux users have had to do some minor udev scripting to make it work (such as this ubuntu user). I too am having problems, but given my unfamiliarity with MIDI and MIDI in arch in particular, I'm struggling to do so.

I suspect I need to construct an appropriate udev rule to allow me to access the device. when I plug in the device, it is successfully recognized:

$ lsusb
Bus 001 Device 007: ID 04d8:eef2 Microchip Technology, Inc. FH-2
# dmesg
usb 1-4: new full-speed USB device number 7 using xhci_hcd
usb 1-4: New USB device found, idVendor=04d8, idProduct=eef2, bcdDevice= 1.72
usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-4: Product: FH-2
usb 1-4: Manufacturer: Expert Sleepers Ltd

the device appears to be assigned /dev/snd/midiC1D0. however, I cannot read or write to it with the web MIDI interface. I suspect this is a udev problem, so I took a stab at writing an appropriate rule:

# vi /etc/udev/rules.d/99-fh2.rules
SUBSYSTEM=="usb", ATTRS{idVendor}=="04d8", ATTR{idProduct}=="eef2", MODE="0660", TAG+="uaccess"
# udevadm control --reload

but this doesn't seem to help.

any ideas as to what I'm missing? how can I troubleshoot this? the ubuntu user linked to above used SUBSYSTEMS=usb-serial; might this be helpful? I'm not familiar enough to know. thanks for your suggestions.

my system:

hardware: dell xps 15 9500 laptop
kernel: 6.5.8-arch1-1

Last edited by dkmb (2023-11-13 03:08:16)