Re: [PARPORT] make lp driver use ECP mode

From: Tim Waugh (
Date: Sun Mar 25 2001 - 06:11:13 EST

  • Next message: Wolfgang Mes: "[PARPORT] Speed in EPP Mode Input"

    On Sun, Mar 25, 2001 at 01:18:45AM +0100, Uwe Bonnes wrote:

    > Why does parport_pc_fifo_write_block_pio poll until the fifo is totally
    > empty? i.m.h.o. it should write to the fifo until it's full and then wait for
    > the fifo interrupt.

    I think (without looking at the code) the idea was that if we can
    catch the FIFO when it's empty, we know how many bytes we can send
    without looking again, and so we can do an IO burst using outsb.

    So I think it's hanging around for a little while to give the FIFO a
    chance to empty so that it can fill it up again quickly.

    That algorithm was never based on empirical evidence though.


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