Re: No scanners identified

From: Eddy De Greef (degreef@imec.be)
Date: Wed Mar 07 2001 - 00:51:30 PST

  • Next message: Jochen Eisinger: "Re: No scanners identified"

    Daniel Karlsson wrote:
    >
    > Eddy De Greef wrote:
    > >
    > > Daniel Karlsson wrote:
    > > >
    > > > I have a Mustek 600 III EP Plus scanner connected to the parallel port.
    > > > When I try to run "scanimage -L" I get a message stating that no
    > > > scanners were identified and that I should try "find-scanner" tool and
    > > > read some documentation. The problem is that I have a parallel port
    > > > scanner, but that program and documentation only covers scsi-scanners.
    > > >
    > >
    > > There are three likely causes for your problem:
    > >
    > > 1) You don't have access to the parallel port.
    > >
    > > You can easily verify if you log in as root and then try to scan.
    > > If that works, you should either run the saned daemon (see
    > > documentation), or make scanimage setuid root (not recommended).
    >
    > It appears to me that the problem is connected to wrong access rights.
    > However, it's not the parallel port, since I can both read and write to
    > it, for instance with "echo Hello > /dev/lp0".
    > The string will then appear on the printer also connected to the port.

    The backend doesn't access the port in that way, I believe. All
    communication with the parallel is performed at the IO-port level
    (ie., IO-ports at addresses 0x380 etc).
    The permissions on /dev/lp0 therefore don't affect the backend.
    A process trying to access the IO-ports must have super-user
    access rights. The proper way to achieve this is to run the sane
    daemon as root (see man saned on how to set it up).

    >
    > Running scanimage as root will cause an error in loading libraries
    > (undefined symbol: outb), which indicates that the program progresses
    > beyond the point described in my problem.

    No idea what is causing this. David Gesswein could be right about
    the optimization issue. Do you have an x86 platform ? I believe
    the low-level assembly routines accessing the io-ports are only
    implemented for x86 hardware.

    Best regards,

    Eddy

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