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

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

Hi 

One thing does puzzles me is that. Same Centos same versions of libusb and python to the very last version number on VirtualBox hosted on Mac OS works fine. 
I posted on stack overflow to get border attention any how here is the link to the question..

https://stackoverflow.com/questions/47087054/pyusb-usb-scanner-read-fails-on-centos-7?noredirect=1#comment81161517_47087054 <https://stackoverflow.com/questions/47087054/pyusb-usb-scanner-read-fails-on-centos-7?noredirect=1#comment81161517_47087054>

Centos 7 with lated kernel update 

CentOS Linux release 7.4.1708


>rpm -qa | grep -i libusb


libusbx-1.0.20-1.el7.x86_64
libusbmuxd-1.0.10-5.el7.x86_64

> On Nov 4, 2017, at 2:53 AM, Tormod Volden <lis...@gm...> wrote:
> 
> On Fri, Nov 3, 2017 at 10:18 PM, Srujan Chaitanya wrote:
>> 
>> Hardware is Dell Precision Tower 3000 Series.
>> 
>> 
>> down votefavorite
> 
> Hello Srujan,
> 
> If you are cross-posting a question from StackOverflow, it would only
> be polite to include a link to the original question.
> 
>> 
>> 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()
> 
> Do you need the reset() here?
Not really just attempting to try if that makes any difference.


> 
>> 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
> 
> The most important difference is probably the version of libusb that
> is in use. Upstream libusb.info is now at 1.0.21. Please be more
> specific about which libusb versions you have on the two systems,
> which versions of the OS, and try a newer version if possible.
> 
> Regards,
> Tormod
> 
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