@SGaist
I'm not sure, but I believe solid needs udev. I'm using busybox with mdev.
However, I found a solution with find and grep.
If I know I have to find where, for instance, sda is connected on my 4 ports:
find /sys/bus/usb/devices/usb*/ -name dev -path "*usb1*sd*" | grep -E sda
find /sys/bus/usb/devices/usb*/ -name dev -path "*usb2-1.1*sd*" | grep -E sda
find /sys/bus/usb/devices/usb*/ -name dev -path "*usb2-1.2*sd*" | grep -E sda
find /sys/bus/usb/devices/usb*/ -name dev -path "*usb2-1.4*sd*" | grep -E sda
The return value is 1 if there is no entry matching and 0 if there is.
I wrapped this in a function with sd_ as variable and it works as supposed.
Cheers,
McL
