[PARPORT] ECP and DMA

From: mark anderson (andersom@frii.com)
Date: Mon Mar 10 2003 - 19:49:56 EST

  • Next message: Duncan Haldane: "[PARPORT] ECP and DMA"

    I'm playing with some home brewed hardware to upload data into
    my linux box. With EPP I'm getting about .5 MBytes/sec. I see
    claims that 2M should be the upper limit. Is there a specific
    mode that runs this fast (EPP/ECP/???). I can make my hardware
    do whatever protocol and timing makes things fastest.

    In a related speed issue, I'd like to use the DMA channel. However,
    I've found a note in the parport bug list (Suse, 2.4.10-4.GB):

    o parport_pc_ecp_read_block_pio() is broken. parport will revert to the
      software-driven mode in ieee1284_ops.c

    Is this telling me that DMA reads under ECP are broken? As I read
    various parallel port documents I'm lead to believe that only ECP
    supports DMA.

    Any thoughts would be appreciated. Thanks.

    --mark

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