Configure udev to change permissions on USB HID device?
Normally, this is done by adding to /etc/udev/rules.d
a file maybe named 50-usb-scale.conf
with contents like this:
SUBSYSTEM=="usb", ATTR{idVendor}=="HEX1", ATTR{idProduct}=="HEX2", MODE="0666"
Where HEX1 and HEX2 are replaced with the vendor and product id respectively.
To match on the Interface type instead, you could try replacing ATTR{idVendor}=="HEX1", ATTR{idProduct}=="HEX2"
with a match for bInterfaceClass
being 03
(HID):
SUBSYSTEM=="usb", ATTR{bInterfaceClass}=="03", MODE="0666"
But be warned, that will catch mice and keyboards too.
Just for the summary:
You may filter for:
- idVendor
- idProduct
- serial
And use:
== Compare for equality.
!= Compare for inequality.
= Assign a value to a key. Keys that represent a list are reset and only this single value is assigned.
+= Add the value to a key that holds a list of entries.
:= Assign a value to a key finally; disallow any later changes.
You may give a specific device a specific new path in /dev/...
Example:
KERNEL=="hiddev*", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="05df", ATTRS{serial}=="1234567", GROUP="cdrom", OWNER="user28", MODE="0640", SYMLINK+="myhid"
Results in:
You can access the device via '/dev/hiddevx' or via '/dev/myhid' easyly, every user in group 'cdrom' may read from the device. Owner 'user28' may read and write.
or simplest:
KERNEL=="hiddev*", ATTRS{idVendor}=="16c0", MODE="0666"
Results in: Every user may access every hiddevice from Vendor 0x16c0
For details see: Docs
In case you need to change (like me) ttyACM0
permissions,
this are my settings:
KERNEL=="ttyACM0", MODE="0777"
It failed when I tried to specify the vendor and product ID. I am not sure why.