USB Device Permissions

[IFD3]

If possible I could need some assistance.
I wanted to try this on a raspberry pi running ubuntu lite

when I try the display.rules in /etc/udev/rules.d/ I still get this message:
usb.core.USBError: [Errno 13] Access denied (insufficient permissions)

if I run it as root it get this:
usb.core.USBTimeoutError: [Errno 110] Operation timed out

at some point I even got this:
AttributeError: 'NoneType' object has no attribute '_ctx'

ID and Vendor match though.
I have no idea if the udev rule need some other name or if there is something else missing. I never worked with USB and udev before in linux.

Maybe some more information on the udev in the readme would help others?

thanks

[ReversingForFun]

I'm not entirely certain but it seems like your flavor of linux may not appreciate the uaccess tag so you may end up needing to modify the udev rule to apply a permission group to the device as follows:

ACTION=="add", SUBSYSTEMS=="usb", DRIVERS=="USB", ATTRS{idVendor}=="3282", ATTRS{idProduct}=="0009", MODE="0660", GROUP="plugdev"

Then simply add the necessary users to the plugdev group for access.

I'll update the readme with some additional details. Thank you!

[IFD3]

i did everythin again on a new install and I am basically back at the start.
Looks like udev rights are ok but I still got usb.core.USBTimeoutError: [Errno 110] Operation timed out
lsusb says:

Bus 001 Device 006: ID 3282:0009
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

Traceback (most recent call last):
File "DisplayPadWorker.py", line 102, in
main()
File "DisplayPadWorker.py", line 44, in main
device.ggSetMainBrightness(0)
File "/home/pi/MountainDisplayPadPy/mountain_displaypad.py", line 292, in ggSetMainBrightness
r = self.__interrupt_out(4, msg)
File "/home/pi/MountainDisplayPadPy/mountain_displaypad.py", line 123, in __interrupt_out
urbtx = self.device_handle.write(endpoint, buffer, timeout)
File "/home/pi/.local/lib/python3.7/site-packages/usb/core.py", line 994, in write
self.__get_timeout(timeout)
File "/home/pi/.local/lib/python3.7/site-packages/usb/backend/libusb1.py", line 860, in intr_write
timeout)
File "/home/pi/.local/lib/python3.7/site-packages/usb/backend/libusb1.py", line 938, in __write
_check(retval)
File "/home/pi/.local/lib/python3.7/site-packages/usb/backend/libusb1.py", line 602, in _check
raise USBTimeoutError(_strerror(ret), ret, _libusb_errno[ret])
usb.core.USBTimeoutError: [Errno 110] Operation timed out

[IFD3]

on a newer Pi with newer python same but different line numbers in libusb:

Traceback (most recent call last):
  File "/home/pi/python/MountainDisplayPadPy/DisplayPadWorker.py", line 102, in <module>
    main()
  File "/home/pi/python/MountainDisplayPadPy/DisplayPadWorker.py", line 44, in main
    device.ggSetMainBrightness(0)
  File "/home/pi/python/MountainDisplayPadPy/mountain_displaypad.py", line 292, in ggSetMainBrightness
    r = self.__interrupt_out(4, msg)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/python/MountainDisplayPadPy/mountain_displaypad.py", line 123, in __interrupt_out
    urbtx = self.device_handle.write(endpoint, buffer, timeout)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/python/MountainDisplayPadPy/venv/lib/python3.11/site-packages/usb/core.py", line 1003, in write
    return fn(
           ^^^
  File "/home/pi/python/MountainDisplayPadPy/venv/lib/python3.11/site-packages/usb/backend/libusb1.py", line 859, in intr_write
    return self.__write(self.lib.libusb_interrupt_transfer,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/python/MountainDisplayPadPy/venv/lib/python3.11/site-packages/usb/backend/libusb1.py", line 942, in __write
    _check(retval)
  File "/home/pi/python/MountainDisplayPadPy/venv/lib/python3.11/site-packages/usb/backend/libusb1.py", line 602, in _check
    raise USBTimeoutError(_strerror(ret), ret, _libusb_errno[ret])
usb.core.USBTimeoutError: [Errno 110] Operation timed out

[ReversingForFun]

I went back and tried to reproduce this and I think it's an issue with the device not waking properly.

On some of my linux systems I've noticed that sometimes the device doesn't actually 'wake up' upon connecting to USB and I've been able to force it to wake by pressing capslock or printscreen on a keyboard. If the displaypad doesn't seem to be lit with the small mountaingg logo on the first key it before running the python code it seems to give the timeout error.

So try that out and let me know whatcha get.

Unfortunately I've yet to figure out what this is about, I'm thinking there's a control transfer that is coming from the windows USB stack or the native software. I'll try to debug this a bit more and see what I can find.

[IFD3]

hmm ok I see, I never had a keyboard connected but I will try tomorrow. thanks so far.