Re: [PARPORT] simple driver

From: Philip Blundell (
Date: Wed Apr 11 2001 - 17:23:55 EDT

  • Next message: Uwe Bonnes: "[PARPORT] Backward compatibility /proc/.../parportX/hardware entry"

    >i am using kernel 2.2.14-12

    Then you need a different signature for your write method. Take a look at,
    say, the lp driver. In particular, yours has too many arguments which is
    probably why you are getting a garbage length turn up.

    >> > copy_from_user(kbuf, buf, count);
    >> This function returns an error flag; you ought to check for success. Also:
    >i checked errno in the program that is using the driver, the code is

    No, I meant you have to check the return value from copy_from_user itself.

    >can you please point to some resource which explains how to use these
    >parport functions and how to build drivers out of these?

    Look in Documentation/parport-lowlevel.txt. Other than that your best bet is
    probably to study the source code of existing drivers.


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