On Sat, Nov 11, 2000 at 08:19:12AM -0500, Mark Abene wrote:

 > I revise my previous statement, and it's good news.  The RTC *can* be used
 > for the jiffy (hz) clock!  I was just reading the code for arc/algor, and
 > the Algorithmics branch does exactly this.  I'm excited.  I was just reading
 > the specs sheet for our DS1287 rtc chip, and it provides a periodic clock
 > interrupt at rates from 500ms down to 122us.  Which makes it perfect for our
 > needs!  So again if the MCT ADR interval timer turns out to be unusable on
 > the Magnum, we have yet another option, and wouldn't have to mess with the
 > cpu timer code at all.  Awesome!

Actually, I just thought of a Really Good reason why we wold not want
to use the Dallas RTC for hardclock -- it's on the "internal devices"
interrupt pin, which is going to be blocked any time you're at e.g.
splbio(), splnet(), etc.

This is, obviously, not good.  If we end up having to use something other
than the ADR interval timer, then it'll have to be the compare register.

-- 
        -- Jason R. Thorpe <thorpej@zembu.com>