[cups.bugs] cups 1.4.3 usb backend fails to detect printers.

Michael Sweet msweet at apple.com
Thu Dec 16 22:27:14 PST 2010


This is a permissions problem - the device file for the USB bus doesn't have read/write for the "lp" user or a corresponding group.

On Dec 15, 2010, at 7:31 AM, Naveen Krishna wrote:

> hi,
> 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)
> linux-gate.so.1 =>  (0xffffe000)
> libcups.so.2 => /usr/lib/libcups.so.2 (0xb7857000)
> libgnutls.so.26 => /usr/lib/libgnutls.so.26 (0xb77da000)
> libpthread.so.0 => /lib/libpthread.so.0 (0xb77c1000)
> libm.so.6 => /lib/libm.so.6 (0xb779b000)
> libcrypt.so.1 => /lib/libcrypt.so.1 (0xb7768000)
> libc.so.6 => /lib/libc.so.6 (0xb7622000)
> libz.so.1 => /usr/lib/libz.so.1 (0xb760e000)
> libgcrypt.so.11 => /usr/lib/libgcrypt.so.11 (0xb75a3000)
> libgpg-error.so.0 => /usr/lib/libgpg-error.so.0 (0xb759f000)
> /lib/ld-linux.so.2 (0xb7892000)
> 
> (with libusb)
> linux-gate.so.1 =>  (0xffffe000)
> libusb-0.1.so.4 => /usr/lib/libusb-0.1.so.4 (0xb76e7000)
> libcups.so.2 => /usr/lib/libcups.so.2 (0xb76b0000)
> libpthread.so.0 => /lib/libpthread.so.0 (0xb7697000)
> libm.so.6 => /lib/libm.so.6 (0xb7671000)
> libcrypt.so.1 => /lib/libcrypt.so.1 (0xb763e000)
> libc.so.6 => /lib/libc.so.6 (0xb74f8000)
> libusb-1.0.so.0 => /usr/lib/libusb-1.0.so.0 (0xb74ec000)
> libz.so.1 => /usr/lib/libz.so.1 (0xb74d8000)
> /lib/ld-linux.so.2 (0xb76ef000)
> librt.so.1 => /lib/librt.so.1 (0xb74cf000)
> 
> I am not sure why 2 versions of libusb are linked. but the difference i observed with them is usr/lib/libusb-1.0.so.0 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..
> 
> --Naveen
> _______________________________________________
> cups-bugs mailing list
> cups-bugs at easysw.com
> http://lists.easysw.com/mailman/listinfo/cups-bugs

________________________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair





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