On 11/23/25 19:14, Michael Wimble wrote:
> For identical devices, I try to plug them into different usb controllers. For a pi you could plug one into a usb2 port and the other into a usb3 port. Then you can write a udev rule using the bus number. In my opinion, udev rules should be used a lot, not avoided. Linux rules for naming devices are a problem to be avoided. I include udev rules in my GitHub.
For *identical* devices, my first preference of avoiding bus numbers and
socket positions does not work. But my Logitec web cam has at least a
serial number which could be used. I prefer vendor and device IDs,
something like
marcow@feather7:/etc/udev/rules.d$ cat 69-mw-serial.rules
ACTION=="add", KERNEL=="ttyACM*", ATTRS{idVendor}=="16c0",
ATTRS{idProduct}=="0483", SYMLINK+="teensy32"
ACTION=="add", KERNEL=="ttyUSB*", ATTRS{idVendor}=="0403",
ATTRS{idProduct}=="6015", SYMLINK+="ublox_f10"
But overall, I think, the udev rules are a good way to create specific
devices names.
-- Marco