USB Permissions

[peteyus]

I'm trying to grant USB permissions so I can use uhubctl to toggle power on my USB ports. Running with sudo it works great, but I'm hitting a wall trying to grant permissions so I can do it without sudo. I have tried both rebooting and the udevadm command to update permissions and still get the permissions error. Am I missing something obvious in granting permissions? Raspberry Pi 2 B v1.1 if that matters.

pi@lego-pi:~ $ uhubctl
No compatible smart hubs detected!
Run with -h to get usage info.
There were permission problems while accessing USB.
To fix this, run this tool as root using 'sudo uhubctl',
or add one or more udev rules like below
to file '/etc/udev/rules.d/52-usb.rules':
SUBSYSTEM=="usb", ATTR{idVendor}=="2001", MODE="0666"
then run 'sudo udevadm trigger --attr-match=subsystem=usb'
pi@lego-pi:~ $ sudo uhubctl
Current status for hub 1-1 [0424:9514, USB 2.00, 5 ports]
  Port 1: 0503 power highspeed enable connect [0424:ec00]
  Port 2: 0100 power
  Port 3: 0100 power
  Port 4: 0100 power
  Port 5: 0100 power
pi@lego-pi:~ $ cat /etc/udev/rules.d/52-usb.rules
SUBSYSTEM=="usb", ATTR{idVendor}=="0424", MODE="0666"

[peteyus]

Additional info it helps, lsusb output:

pi@lego-pi:~ $ lsusb
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

[peteyus]

Answered myself, I noticed the last root hub entry from lsusb had a different device ID. Adding this line to my 52-usb.rules file fixed it:

SUBSYSTEM=="usb", ATTR{idVendor}=="1d6b", MODE="0666"

[mvp]

You are using old version of uhubctl. If you used uhubctl 2.4.0, this warning would not be shown (and it is actually irrelevant for you controlling hub 1-1 [0424:9514]).
More here: https://github.com/mvp/uhubctl/releases/tag/v2.4.0 and 9b5efa0.

[snyper0971]

I am having an issue getting the Permissions to work on a Raspberry PI 2B running the latest buster. I have 2.4.0 installed. Am I missing something?

pi@octopi:~ $ cat /etc/udev/rules.d/52-usb.rules
SUBSYSTEM=="usb", ATTR{idVendor}=="0424", MODE="0666

pi@octopi:~ $ uhubctl -n 0424 -a on -p 2
There were permission problems while accessing USB.
Follow https://git.io/JIB2Z for a fix!
No compatible devices detected!
Run with -h to get usage info.

pi@octopi:~ $ sudo uhubctl -n 0424 -a on -p 2
Current status for hub 1-1 [0424:9514, USB 2.00, 5 ports, ppps]
  Port 2: 0100 power
Sent power on request
New status for hub 1-1 [0424:9514, USB 2.00, 5 ports, ppps]
  Port 2: 0100 power

[mvp]

Did you reboot your device after creating rules file?

[snyper0971]

1st I tried sudo udevadm trigger --attr-match=subsystem=usb then I tried a reboot. I still get the results above.

[mvp]

This is weird. The only way to get this error is if get_hub_info() call fails for hub 0424:9514 when not running as root:

uhubctl/uhubctl.c

Lines 708 to 712 in 69c444b

	rc = get_hub_info(dev, &info);
	if (rc) {
	perm_ok = 0; /* USB permission issue? */
	continue;
	}

I recommend to either add few more debugging printf() statements around to understand why it fails, or if you have gdb installed on your Pi, run uhubctl under gdb using something like this:

$ gdb uhubctl
gdb> set args -n 0424 -a on -p 2
gdb> b get_hub_info
gdb> c
gdb> # from here use n(ext), s(ub) or p variable to debug

[mvp]

@snyper0971: are you sure you configured it properly? This does not look right:

SUBSYSTEM=="usb", ATTR{idVendor}=="0424", MODE="0666

It should be (note extra double quote):

SUBSYSTEM=="usb", ATTR{idVendor}=="0424", MODE="0666"

[snyper0971]

Great catch! Always something small and simple.... That did the trick, thank you!

[ecnelson]

How about sudo chmod u+s /usr/sbin/uhubctl

I have a python daemon running as user 'pi' that occasionally gets IO Errors from an FTDI gadget. The errors persist even after the daemon restarts. It could be pilot error on my part, or the gadget itself may be on its way out (I've had one fail before). In the meantime, what does seem to fix it is removing and reinserting the FTDI gadget. Some of these devices (RaspberryPis feeding environmental data) are remote, so uhubctl is perfect! Thank you for inventing it.

That said, sudo in a python script is a potential issue, so I just set the setuid bits on uhubctl. What could go wrong, eh?

[mvp]

Don't set suid, it could be security issue if uhubctl has a bug. Instead, follow readme on how to set USB permissions properly, it will make it work without suid.