RE: [PARPORT] Clean IEEE1284 termination

From: Chandan Mishra (
Date: Mon Mar 06 2000 - 15:49:22 EST

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    Another question (s) related to ppdev driver.
    1. No handshaking is done in PPSETMODE ioctl command. What is use of this
    ioctl command.
       Doesn't using just PPNEGOT suffice.

    2. What is use of PPSETPHASE command. Isnt this supposed to be handled
    internally by the driver.

    3. Also whats the use of PPDATADIR commnad. Driver shld automatically change
    the data direction if I am reading after writing and writing after reading.
    Why should user bother about all this.

    Can somebody help me with these questions? Or point me to appropriate
    documentation for ppdev driver.


    > -----Original Message-----
    > From: Greg Nelson []
    > Sent: Monday, March 06, 2000 9:31 AM
    > To:
    > Cc:
    > Subject: [PARPORT] Clean IEEE1284 termination
    > I want to check something simple here (I'm working with kernel
    > 2.3.42).
    > parport_ieee1284_terminate seems to be the only place where the
    > handshaking is done to return the port to compatibility mode. (Good.)
    > parport_negotiate seems to be the only place
    > parport_ieee1284_terminate is called.
    > My best understanding is that closing the port leads to calls to
    > pp_release, parport_release (if claimed), and
    > parport_unregister_device (if pdev non-NULL). I can't find anything
    > that would guarantee, at the kernel level, that the port is cleanly
    > returned to compatibility mode when the port is closed.
    > Does this have to be done at the application level, by renegotiating
    > compatibility mode or something like that?
    > Thanks,
    > Greg Nelson
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