[LinuxPPS] PLL sensitivity

[Hal V. Engel]

On Tuesday 18 November 2008 08:04:42 Udo van den Heuvel wrote:
> Rodolfo Giometti wrote:
> > On Mon, Nov 17, 2008 at 07:04:25PM +0100, Udo van den Heuvel wrote:
> >> At the url you posted I read:
> >>
> >>  As an aside, time_pps_kcbind() may be optional, but it isn't
> >>  terribly difficult to implement. You do yourself a disservice by
> >>  not suporting it, IMO.
> >>
> >> So Rodolfo, what do you say?
> >
> > Sorry but I cannot help here, I'm terribly busy on other projects. :'(
> >
> > If you wish implement time_pps_kcbind() you are welcomed. Please, then
> > send the patch to this list for review.
>
> So: anybody?
> What info do we need before we can start to (pseudo) code the function?

I had a quick look at this function in the FreeBSD source code yesterday.  But 
it looked overly simple to me and all it really does is pass the call to the 
ioctl function with the right parms.  I didn't dig much father but it appears 
that in order to make this work the kernel will need to have some of the same 
functionality that is currently in ntpd and I don't know if this functionality 
exists in the kernel.  If it does then implementing time_pps_kcbind() should 
be almost trivial although I suspect that this part of the kernel will be 
untested if it exists. But if it does not then the real issue is implementing 
the kernel time keeping consumer which is likely to be non-trivial.   Perhaps 
someone who is more familiar with this can comment.

Hal