[pyusb-users] Centos 7 Usb Barcode scanner not able to read.

[Srujan C. <sri...@gm...>]

Hardware is Dell Precision Tower 3000 Series.





> 
> down vote
>  <>favorite
>  <https://stackoverflow.com/questions/47087054/pyusb-usb-scanner-read-fails-on-centos-7#>	
> I'm trying to implement driver mechanism for usb barcode scanner on Centos.
> 
> Using PyUSB,
> 
> Here is high-level code. I am trying to achieve is to be able to read QR-Codes and BarCodes when someone scans and send it to message queue without user interaction.
> 
> dev = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
> if dev.is_kernel_driver_active(0) is True:
>     dev.detach_kernel_driver(0)
> dev.set_configuration()
> dev.reset()
> data = dev.read(endpoint.bEndpointAddress, 120,
>                     timeout=10000)
> currentData = list(chunks(data))
> This code work fine on the same system with Ubuntu operating system. But on Centos 7 , All I hear rapid beeps, and nothing read from the scanner.
> 
> Here is everything installed on Centos, almost similar to Ubuntu that I ran on the same machine.
> 
> "libgusb.x86_64                         0.2.9-1.el7                     @base
> libgusb-devel.x86_64                   0.2.9-1.el7                     @base
> libusb.x86_64                          1:0.1.4-3.el7                   @base
> libusb-devel.x86_64                    1:0.1.4-3.el7                   @base
> libusbmuxd.x86_64                      1.0.10-5.el7                    @base
> libusbmuxd-devel.x86_64                1.0.10-5.el7                    @base
> libusbmuxd-utils.x86_64                1.0.10-5.el7                    @base
> libusbx.x86_64                         1.0.20-1.el7                    @base
> libusbx-devel.x86_64                   1.0.20-1.el7                    @base
> pyusb.noarch                           1.0.0-0.11.b1.el7               @base
> usb_modeswitch.x86_64                  2.4.0-5.el7                     @base
> usb_modeswitch-data.noarch             20160612-2.el7                  @base
> usbmuxd.x86_64                         1.1.0-1.el7                     @base
> usbredir.x86_64                        0.7.1-2.el7                     @base
> usbutils.x86_64                        007-5.el7                       @base"
> Not sure what's the isse.
> 
> If I run, bellow block in loop,
> 
>  print("Waiting to Read")
>  data = dev.read(endpoint.bEndpointAddress, 120,
>                     timeout=10000)
>  currentData = list(chunks(data))
> Output is Waiting to read
>