Re: [PARPORT] How parport can perform inp/outp ?

From: Tim Waugh (
Date: Wed Mar 08 2000 - 06:48:19 EST

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    On Wed, 8 Mar 2000, DAANEN Vincent wrote:

    > I'm trying to write my own modules to access to a parallel device I
    > did. I look in parport source but can't find any reference to ioperm
    > whereas I found lots of references to inp, outp. Does using parport
    > needs root permissions? If not, why can parport access without ioperm
    > nor iopl ?

    The parport code is in-kernel. It's nothing like a normal user process,


    > Supposing I create a device /dev/mydevice and loaded mydevice.o
    > module, does a simply chmod 666 /dev/mydevice will give me permissions
    > to read and write from external world via the parallel port ?

    Unless your driver does specific checks for uid==0, yes.


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