[Bug 1890572] Re: USB backend never ends if the printer is not connected

Till Kamppeter 1890572 at bugs.launchpad.net
Mon Apr 12 14:59:33 UTC 2021


Please report on the new GitHub of CUPS on OpenPrinting:

https://github.com/OpenPrinting/cups/issues

On Apple the CUPS project is dead and bug reports probably not read any
more.

-- 
You received this bug notification because you are a member of Ubuntu
Sponsors Team, which is subscribed to the bug report.
https://bugs.launchpad.net/bugs/1890572

Title:
  USB backend never ends if the printer is not connected

Status in cups package in Ubuntu:
  New

Bug description:
  USB backend never ends if the printer is not connected. We have been
  able to identify a infinity loop in print_device function in usb-
  libusb.c file:

  ```
    fprintf(stderr, "DEBUG: Printing on printer with URI: %s\n", uri);
    while ((g.printer = find_device(print_cb, uri)) == NULL)
    {
      _cupsLangPrintFilter(stderr, "INFO",
      _("Waiting for printer to become available."));
      sleep(5);
    }
  ```

  It's also easy to test by invoking the backend by hand:

  ```
  # export DEVICE_URI='usb://Printer/Model?serial=?'
  # /usr/lib/cups/backend/usb 0 root title 1 '' data.file

  DEBUG: Loading USB quirks from "/usr/share/cups/usb".
  DEBUG: Loaded 159 quirks.
  DEBUG: Printing on printer with URI: usb://Printer/Model?serial=?
  DEBUG: libusb_get_device_list=6
  INFO: Waiting for printer to become available.
  DEBUG: libusb_get_device_list=6
  INFO: Waiting for printer to become available.
  DEBUG: libusb_get_device_list=6
  INFO: Waiting for printer to become available.
  DEBUG: libusb_get_device_list=6
  INFO: Waiting for printer to become available.
  DEBUG: libusb_get_device_list=6
  INFO: Waiting for printer to become available.
  ...

  ```

  Setting a job timeout policy or manually stopping work are not options
  for us. We may have jobs that take hours to complete.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1890572/+subscriptions



More information about the Ubuntu-sponsors mailing list