[PARPORT] EPP speed results on ppdev

chris (clfletch@spawar.navy.mil)
Mon, 22 Nov 1999 11:03:52 -0800

Hi parport specialists,
    I sent this message last Thursday, but I do not think it got out
correctly. Anyway here it is again.

   I have built the 2.3.28 development kernel and have used it to
perform EPP data read transfer through the parallel port at data rates
around 340Kbytes/sec, which I believe is still a little slower than it
should be. In addition there seems to be some data dropouts.

    After looking at the timing on a logic analyzer I noticed that
between reading in a bytes there is about a 3microsecond delay period
before the parallel port is ready to read in another byte. Is clearing
the timeout bit before each data read cycle a necissity?

    What about block transfers has anybody tried that with the ppdev
driver in EPP mode?

    I did notice that there was pp_mmap in the pp_fops but it was NULL.
Is there any plan on using the pp_mmap file operation or is it a work in


    Thanks for the help

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This archive was generated by hypermail 2.0b3 on Wed 24 Nov 1999 - 11:27:50 EST