Re: Problems with Acer ScanPrisa 640S

From: Sebastien Sable (sebastien.sable@gmx.net)
Date: Fri Oct 20 2000 - 17:53:57 PDT

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    Steve Underwood <steveu@coppice.org> writes:

    > I updated the backend to merge the colours properly in May. Since then I have had
    > little feedback. Lawrence is the first person to fully work through anything from
    > "I have a problem" to "I have a cure" since then. People need some serious coaxing

    This time I think "I have a cure" ;)

    I found that ps->pss->expected_read_bytes calculated in SCSISource_get
    was slowly decreasing down to 0. At this point
    (ps->pss->expected_read_bytes == 0) the scanner would block.

    To solve this, I can put it to an arbitrary high value.

    // ps->pss->expected_read_bytes =
    // ((int) (msecs/ps->pss->ms_per_line))*ps->pss->bytes_per_line;

            ps->pss->expected_read_bytes = 50000;

    then this line later
            ps->pss->expected_read_bytes = MIN(ps->pss->expected_read_bytes,
                                               (size_t) ps->absolute_max);
    put it to absolute_max.

    In this case, my scanner works fine and does not block anymore. Of
    course, it's a dirty trick.
    May be the ms_per_line reported by the scanner is not right or
    something?

    -- 
    Sébastien Sablé
    sebastien.sable@gmx.net
    

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