Re: [PARPORT] ECP FIFO residue

From: Tim Waugh (twaugh@redhat.com)
Date: Tue Jun 12 2001 - 04:37:43 EDT

  • Next message: Tim Waugh: "Re: [PARPORT] ECP FIFO residue"

    On Tue, Jun 12, 2001 at 09:53:27AM +0200, Laurent Pinchart wrote:

    > My second idea was to save it in struct pardevice. That solves the
    > problem of 'sharing' residues among several devices, but how can I
    > access that struct pardevice when in parport_pc_ecp_read_block_pio ?

    Yes, struct pardevice is the right place I think. You can access it
    at port->physport->dev.

    However, I'm not too sure that I'm happy about this situation:

    - client negotiates to ECP mode
    - FIFO fills up
    - client asks for 1 byte of data.
    - we block the FIFO and read it all in, giving 1 byte back to
      application
    - client terminates back to compatibility mode
    [... another client comes along, and goes... ]
    - client negotiates back to ECP mode and asks for data
    - we give it the data we remembered from before

    I think we need to forget the data once the client has terminated back
    to compatibility mode. The reason is that there are some things (like
    device ID) which are defined like this.

    Tim.
    */



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