[cups] Cups usb printer discovery problems

Helge Blischke HelgeBlischke at web.de
Wed Sep 10 04:10:23 PDT 2014


For your information:
on my Ubuntu based Linux installation (Peppermint 3) the permissions  
uf the USB backend are:
-r-xr--r-- 2 root root 30416 Jul 18 23:12 usb
and the USB devices look like
crw-------  1 root root    252,   0 Sep 10 06:15 usbmon0

Since I currently have no USB printer at hand, I cannot test it now.
BTW, the CUPS version on this machine is 1.5.3 .

Helge


Am 09.09.2014 um 12:27 schrieb Michael Sweet:

> Eugene,
>
> The USB backend is not run as root. You need to make sure the USB  
> device files can be accessed by the lp user or corresponding group  
> for your platform.
>
>
> Sent from my iPad
>
> On Sep 9, 2014, at 5:03 AM, Eugene Prokopiev <enp at itx.ru> wrote:
>
>>>> Run "cupsctl --debug-logging" and then look at /var/log/cups/ 
>>>> error_log when you go to add the printer.
>>>
>>> I can't see nothing interesting in error_log, so I attached it.
>>
>> Sorry, previous file was wrong, so I attached another one. The
>> interesting part looks like:
>>
>> D [09/Sep/2014:17:31:33 +0400] [CGI] list_devices
>> D [09/Sep/2014:17:31:33 +0400] [CGI] libusb_get_device_list=7
>> D [09/Sep/2014:17:31:33 +0400] [CGI] Failed to open device, code: -3
>>
>> It looks as permissions problem, but how can it be with root  
>> privileges?
>>
>> -- 
>> WBR,
>> Eugene Prokopiev
>> _______________________________________________
>> cups mailing list
>> cups at cups.org
>> https://www.cups.org/mailman/listinfo/cups
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