[PATCH] sanei_scsi.c for dio in Linux

From: Douglas Gilbert (dgilbert@interlog.com)
Date: Sun Apr 01 2001 - 08:00:36 PDT

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    Together with Abel Deuring I have been doing some testing
    using "direct IO" to speed data transfers with SANE when
    using lk 2.4 kernels. Abel has had the code in place for
    a while (both in 1.0.3 and 1.0.4) but it hasn't yet been
    used in "anger". Anyway I found a small problem and have
    been unable to contact Abel. Since I don't have CVS access
    perhaps someone could apply the patch below.

    --- sane-backends-1.0.4/sanei/sanei_scsi.c Thu Nov 30 15:02:30 2000
    +++ sane-backends-1.0.4/sanei/sanei_scsi.c_dio Sun Apr 1 10:38:55 2001
    @@ -2022,7 +2022,7 @@
               else
                 {
                  /* check for errors, but let the sense_handler decide.... */
    - if ( (req->sgdata.sg3.hdr.info && SG_INFO_CHECK != 0)
    + if ( (req->sgdata.sg3.hdr.info & SG_INFO_CHECK != 0)
                      || (req->sgdata.sg3.hdr.sb_len_wr > 0 &&
                      ((req->sgdata.sg3.sense_buffer[0] & 0x7f) != 0)))

    For any adventurous people who have a fast scsi scanner and
    are running lk 2.4 then to test this you will need to get
    sg version 3.1.18 (at http://www.torque.net/sg ), apply
    the above patch and rebuild SANE. First try a scan to make
    sure everything is still working. Then do
    "echo 1 > /proc/scsi/sg/allow_dio" and try to scan again.
    It works for me, but given the data transfer speed of my
    UMAX 1220S, it is hardly likely to make a measurable
    performance impact. I would be interested in reports.

    Doug Gilbert

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