ValueError: The device has no langid

[jedie]

I have a Polar A360, Firmware v1.2.60, HW-Model 00756861.01

Traceback (most recent call last):
  File "__main__.py", line 285, in <module>
    main()
  File "__main__.py", line 278, in main
    cli.cmdloop(__INTRO.format(__version__))
  File "/usr/lib/python2.7/cmd.py", line 142, in cmdloop
    stop = self.onecmd(line)
  File "/usr/lib/python2.7/cmd.py", line 221, in onecmd
    return func(arg)
  File "__main__.py", line 75, in do_list
    info = Device.get_info(dev)
  File "/media/servershare/repos/polar_venv/src/loophole/loophole/polar/__init__.py", line 660, in get_info
    return usb.get_info(usb_device)
  File "/media/servershare/repos/polar_venv/src/loophole/loophole/polar/__init__.py", line 578, in get_info
    return self.usb.get_info(usb_device)
  File "/media/servershare/repos/polar_venv/src/loophole/loophole/polar/__init__.py", line 476, in get_info
    info['manufacturer'] = self.usb.util.get_string(usb_device, usb_device.iManufacturer)
  File "/media/servershare/repos/polar_venv/src/pyusb/usb/util.py", line 314, in get_string
    raise ValueError("The device has no langid")
ValueError: The device has no langid

$ lsusb 
...
Bus 001 Device 004: ID 0da4:0008 Polar Electro Oy Loop
...

the print output of Device.list() entry is:

0 DEVICE ID 0da4:0008 on Bus 001 Address 004 =================
 bLength                :   0x12 (18 bytes)
 bDescriptorType        :    0x1 Device
 bcdUSB                 :  0x200 USB 2.0
 bDeviceClass           :    0x0 Specified at interface
 bDeviceSubClass        :    0x0
 bDeviceProtocol        :    0x0
 bMaxPacketSize0        :   0x40 (64 bytes)
 idVendor               : 0x0da4
 idProduct              : 0x0008
 bcdDevice              :  0x100 Device 1.0
 iManufacturer          :    0x1 Error Accessing String
 iProduct               :    0x2 Error Accessing String
 iSerialNumber          :    0x3 Error Accessing String
 bNumConfigurations     :    0x1
  CONFIGURATION 1: 350 mA ==================================
   bLength              :    0x9 (9 bytes)
   bDescriptorType      :    0x2 Configuration
   wTotalLength         :   0x29 (41 bytes)
   bNumInterfaces       :    0x1
   bConfigurationValue  :    0x1
   iConfiguration       :    0x4 Error Accessing String
   bmAttributes         :   0x80 Bus Powered
   bMaxPower            :   0xaf (350 mA)
    INTERFACE 0: Human Interface Device ====================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x0
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x2
     bInterfaceClass    :    0x3 Human Interface Device
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x5 Error Accessing String
      ENDPOINT 0x81: Interrupt IN ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x81 IN
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1
      ENDPOINT 0x1: Interrupt OUT ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :    0x1 OUT
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1

virtualenv info:

$ pip freeze
appdirs==1.4.3
packaging==16.8
pkg-resources==0.0.0
protobuf==3.2.0
pyparsing==2.2.0
-e git+https://github.com/walac/pyusb.git@1f66ccd5d252e969b1de9bf91bf24e5c64294b8d#egg=pyusb
six==1.10.0

[jedie]

It works as root using sudo...

Related stuff around permissions:
https://github.com/walac/pyusb/issues/139
padelt/temper-python#63

Maybe we can add a message like this:
padelt/temper-python@69034a4

[rsc-dev]

Great. 04.04.2017 08:58 "Jens Diemer" <notifications@github.com> napisał(a):

…

It works as root using sudo... Related stuff around permissions: walac/pyusb#139 <https://github.com/walac/pyusb/issues/139> padelt/temper-python#63 <padelt/temper-python#63> Maybe we can add a message like this: ***@***.*** <padelt/temper-python@69034a4> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#8 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AMYybw3BpiK-wP-UYNa_KRZv2Fw-G9Mfks5rsen3gaJpZM4Mw3AD> .

[jedie]

The output with #9 looks like this:

$ python loophole/__main__.py


 _|                                _|                  _|
 _|    _|_|      _|_|    _|_|_|    _|_|_|      _|_|    _|    _|_|
 _|  _|    _|  _|    _|  _|    _|  _|    _|  _|    _|  _|  _|_|_|_|
 _|  _|    _|  _|    _|  _|    _|  _|    _|  _|    _|  _|  _|
 _|    _|_|      _|_|    _|_|_|    _|    _|    _|_|    _|    _|_|_|
                         _|
                         _|
                                                           ver. 0.5

loophole(no device)>list
Device no: 0
Device info:
DEVICE ID 0da4:0008 on Bus 001 Address 003 =================
 bLength                :   0x12 (18 bytes)
 bDescriptorType        :    0x1 Device
 bcdUSB                 :  0x200 USB 2.0
 bDeviceClass           :    0x0 Specified at interface
 bDeviceSubClass        :    0x0
 bDeviceProtocol        :    0x0
 bMaxPacketSize0        :   0x40 (64 bytes)
 idVendor               : 0x0da4
 idProduct              : 0x0008
 bcdDevice              :  0x100 Device 1.0
 iManufacturer          :    0x1 Error Accessing String
 iProduct               :    0x2 Error Accessing String
 iSerialNumber          :    0x3 Error Accessing String
 bNumConfigurations     :    0x1
  CONFIGURATION 1: 350 mA ==================================
   bLength              :    0x9 (9 bytes)
   bDescriptorType      :    0x2 Configuration
   wTotalLength         :   0x29 (41 bytes)
   bNumInterfaces       :    0x1
   bConfigurationValue  :    0x1
   iConfiguration       :    0x4 Error Accessing String
   bmAttributes         :   0x80 Bus Powered
   bMaxPower            :   0xaf (350 mA)
    INTERFACE 0: Human Interface Device ====================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x0
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x2
     bInterfaceClass    :    0x3 Human Interface Device
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x5 Error Accessing String
      ENDPOINT 0x81: Interrupt IN ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x81 IN
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1
      ENDPOINT 0x1: Interrupt OUT ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :    0x1 OUT
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1
-------------------------------------------------------------------------------
Traceback (most recent call last):
  File "loophole/__main__.py", line 301, in <module>
    main()
  File "loophole/__main__.py", line 294, in main
    cli.cmdloop(__INTRO.format(__version__))
  File "/usr/lib/python2.7/cmd.py", line 142, in cmdloop
    stop = self.onecmd(line)
  File "/usr/lib/python2.7/cmd.py", line 221, in onecmd
    return func(arg)
  File "loophole/__main__.py", line 88, in do_list
    ) % err
ValueError: Can't get device info. Origin Error: The device has no langid
Maybe this is a permission issue.
Please read section 'permission' in README ;)

[jedie]

The interesting question is: How to use the USB device without root!

I found:
http://stackoverflow.com/questions/3738173/why-does-pyusb-libusb-require-root-sudo-permissions-on-linux

so maybe create a udev role?!?
Maybe print in the error message a example udev role?!? This information is available. See the print output from above:

...
DEVICE ID 0da4:0008 on Bus 001 Address 003
...

Don't know to get the IDs directly.

[rsc-dev]

Insufficient permissions for USB. Exception handling implemented.
@jedie Thanks!!