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List:       comedi
Subject:    NI PCI board w/ SCXI extensions.
From:       "Caleb Tennis" <caleb () aei-tech ! com>
Date:       2001-07-03 22:03:33
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I recently patched in Brad Keryan's SCXI code into my comedi 0.7.59 and
comedilib 0.7.15 with almost complete success.  In fact, I modified the
problems I was having and compiled it, ran some samples, and it worked
great.

The problem I had was with the nanodelay function he wrote (which, in an
earlier patch was called comedi_ndelay).  This function references a global
variable called "loops_per_sec", which as best as I can tell is a variable
specific to the kernel itself.

When I compiled this program in 2.2.16, everything went off fine.  However,
when I tried to compile in 2.2.19, it didn't work.  I noticed in the kernel
source that references to "loops_per_sec" had been changed to
"loops_per_jiffy".  Upon making that replacement, the program still didn't
compile.

In his most recent patch (for comedi 0.7.56), Brad had put this function
into comedidev.h.  In his original patch (for 0.7.53), Brad had this
function located in drivers.c.

If I put this function into comedidev.h, it complains that it has never
heard of "loops_per_jiffy".  If I put this function into drivers.c, the
driver compiles, but upon trying to insmod it I get told that no symbol
exists for nanodelay.  If I add an EXPORT_SYMBOL(nanodelay) to the
comedi_ksyms.c file (something Brad had done for the original comedi_ndelay
but not the nanodelay), the driver doesn't compile and I can't remember the
error off the top of my head.

In the mean time, I just told the nanodelay function to do a udelay(1)
instead of calculating a nanosecond delay.

Anyone have any ideas on this, or do I need to post some screen dumps?

Thanks, and have a great Independence Day (for all of the USers).

Caleb Tennis
Analytical Engineering, Inc.
2555 Technology Blvd.
Columbus, IN  47201
http://www.aei-tech.com




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