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linuxusbdetectcups

Cups-2.2.5 can't display local printer on GUI when i click "Add Printer"

This is a strange issue.

I am porting CUPS-2.2.5 to mips-linux, but i can't see local printer on Web Interface when i try to "Add Printer". Then i use "lpinfo -v" under command line, there are some info output as picture: lpinfo -v

Similarly, we can't see any usb device. However, i execute CUPS backend program "usb", can see usb device info, as below: /mnt/apps/lib/cups/backend/usb Anybody has any think?

Thanks.

Solution

  • I found the key of this issue. It is a permisson wrong about "/mnt/apps/lib/cups/backend/usb". Below from official website https://www.cups.org/doc/man-backend.html:

    "Backends can also be installed with restricted permissions (0500 or 0700) that tell the scheduler to run them as the "root" user instead of an unprivileged user (typically "lp") on the system."

    Before i always execute command "chmod 755 " under derectory /mnt/apps/lib/cups/backend, then i can't see usb printer. Still i change backend/ permission to 700, local usb printer display on GUI.