[cups.development] CUPS not detect the USB printer connected

Michael Sweet msweet at apple.com
Fri Sep 3 08:19:42 PDT 2010


Either add a group and use it for the USB files and the Group directive in cupsd.conf, or chmod the USB backend to mode 0500 so that it runs as root.

On Sep 3, 2010, at 12:15 AM, Senthil Murugan wrote:

> Michael,
> 
> My development environment is so customized. i dont' have many groups. i have only root and admin as user. and root as group.
> 
> So, i have change the permission to group as Read&Write. Is it any still require the file /dev/usb/lp0 should be in "sys" group?
> 
> Thanks,
> Senthil
> 
> 
>> The files need a different group (whichever group is in cupsd.conf - =
>> usually "sys"...)
>> 
>> On Sep 2, 2010, at 10:38 PM, Senthil Murugan wrote:
>> 
>>> Michael,
>>> =20
>>> Here the /dev/usb/* file permission details,
>>> =20
>>> crw-rw----    1 root     root     180,   0 Jan  1 00:09 lp0
>>> crw-rw----    1 root     root     180,   1 Jan  1 00:10 lp1
>>> =20
>>> In /etc/cups/cupsd.conf enable the debug level as "debug2" and i could =
>> see the polling process detects only 5 fd some time. some time it shows =
>> 7 fd.
>>> =20
>>> [02/Jan/1970:17:14:10 +0000] cupsdDoSelect: Read on fd 5...
>>> this may give some info to you on the problem part.
>>> =20
>>> Thanks,
>>> Senthil
>>> =20
>>>> You need to check the permissions of the /dev/usb/* files.
>>>> =20
>>>> On Sep 2, 2010, at 7:25 AM, Senthil Murugan wrote:
>>>> =20
>>>>> Thanks Michael for quick input. OpenWrt for embedded device not =
>> having =3D
>>>> all the users in my config. I have only root user and admin user. I =
>> have =3D
>>>> root permission for the /usr/lib/cups/backend/usb. owner and group =3D
>>>> permission also for user root. I login as a root and executes lpinfo =
>> -v. =3D
>>>> its shows only 5 devices. Same time when i change the directory =3D
>>>> /usr/lib/cups/backend/ run "usb" i could able to see the printer =
>> details =3D
>>>> including serial number.
>>>>> =3D20
>>>>> Thanks,
>>>>> Senthil
>>>>> =3D20
>>>>>> Sounds like a permissions problem - the USB backend runs as the =
>> "lp" =3D
>>>> =3D3D
>>>>>> user by default, so the USB device files will need to be writable =
>> by =3D
>>>> =3D3D
>>>>>> "lp" or have the appropriate group with group write enabled.
>>>>>> =3D20
>>>>>> On Sep 1, 2010, at 6:06 AM, Senthil Murugan wrote:
>>>>>> =3D20
>>>>>>> Hi Team,
>>>>>>> =3D3D20
>>>>>>> I'm working on the embedded system with OpenWrt plus CUPS 1.3.10. =
>> =3D3D
>>>>>> lpinfo -v not listing my usb printer connected. I could see the =3D
>>>> device =3D3D
>>>>>> connected in /proc/bus/usb/devices & /usr/share/cups/backend/usb =
>> also =3D
>>>> =3D3D
>>>>>> shows the printer connected. But my lpinfo -v command shows always =
>> 5 =3D
>>>> =3D3D
>>>>>> other devices (http, ipp, socket, lpd & scsi).
>>>>>>> =3D3D20
>>>>>>> went through some extend of debug by enabling DEBUG option in code =
>> =3D3D=3D
>>>> =20
>>>>>> (debug.h). when i enable DEBUG option lpinfo -v hangs.
>>>>>>> =3D3D20
>>>>>>> Looking experts input to resolve my problem.
>>>>>>> =3D3D20
>>>>>>> Thanks,
>>>>>>> Senthil
>>>>>>> _______________________________________________
>>>>>>> cups-dev mailing list
>>>>>>> cups-dev at easysw.com
>>>>>>> http://lists.easysw.com/mailman/listinfo/cups-dev
>>>>>> =3D20
>>>>>> =3D
>>>> =
>> ________________________________________________________________________
>>>>>> Michael Sweet, Senior Printing System Engineer, PWG Chair
>>>>>> =3D20
>>>>>> =3D20
>>>>>> =3D20
>>>>>> =3D20
>>>>> =3D20
>>>>> _______________________________________________
>>>>> cups-dev mailing list
>>>>> cups-dev at easysw.com
>>>>> http://lists.easysw.com/mailman/listinfo/cups-dev
>>>> =20
>>>> =
>> ________________________________________________________________________
>>>> Michael Sweet, Senior Printing System Engineer, PWG Chair
>>>> =20
>>>> =20
>>>> =20
>>>> =20
>>> =20
>>> _______________________________________________
>>> cups-dev mailing list
>>> cups-dev at easysw.com
>>> http://lists.easysw.com/mailman/listinfo/cups-dev
>> 
>> ________________________________________________________________________
>> Michael Sweet, Senior Printing System Engineer, PWG Chair
>> 
>> 
>> 
>> 
> 
> _______________________________________________
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> cups-dev at easysw.com
> http://lists.easysw.com/mailman/listinfo/cups-dev

________________________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair








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