cups 1.4.3 usb backend fails to detect printers.

Naveen Krishna naveen.yarlagadda at
Wed Dec 15 07:31:59 PST 2010

 I have encountered a problem with the 'usb' backend of cups 1.4.3. The backend is not able to detect the USB printer (HP LaserJet 1320). If I specify "--disable-libusb" while configuring cups, it is detecting the devices.

The details of the shared libs for the usb backend executable with & without libusb are as follows resp.

(without libusb) =>  (0xffffe000) => /usr/lib/ (0xb7857000) => /usr/lib/ (0xb77da000) => /lib/ (0xb77c1000) => /lib/ (0xb779b000) => /lib/ (0xb7768000) => /lib/ (0xb7622000) => /usr/lib/ (0xb760e000) => /usr/lib/ (0xb75a3000) => /usr/lib/ (0xb759f000)
/lib/ (0xb7892000)

(with libusb) =>  (0xffffe000) => /usr/lib/ (0xb76e7000) => /usr/lib/ (0xb76b0000) => /lib/ (0xb7697000) => /lib/ (0xb7671000) => /lib/ (0xb763e000) => /lib/ (0xb74f8000) => /usr/lib/ (0xb74ec000) => /usr/lib/ (0xb74d8000)
/lib/ (0xb76ef000) => /lib/ (0xb74cf000)

 I am not sure why 2 versions of libusb are linked. but the difference i observed with them is usr/lib/ has no function usb_init().

 Also, when using the libusb, the o/p observed when the usb backend executable run from the command prompt.
DEBUG: list_devices
DEBUG: usb_find_busses=4
DEBUG: usb_find_devices=6

But when seen in the cups error_log, it is something like
[Job 41]list_devices
[Job 41]usb_find_busses=0
[Job 41]usb_find_devices=0
Waiting for printer to become available...

 I would appreciate any help in this regard. Thanks in advance..


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