[LinuxPPS] Followup on PPS problem.

[clemens at dwf.com]

> On Fri, Jun 27, 2008 at 12:00 AM,  <clemens at dwf.com> wrote:
> > Just a followup on my previous note.
> > I have rebuilt my kernel with 2.6.24.4 and the quinquies patch.
> >
> > Nothing has changed (surprise)
> > w/o the sleep ntpd doesnt start (cant open /dev/pps1)
> > with the sleep 5 it works fine.
> >
> 
> The only thing I can think of is that there is data in the old ldisc
> or something like that.  I would have expected a change in ldisc to
> result in incoming/outgoing buffers being dumped or at least flushed
> and the new ldisc to take effect almost immediately.  Maybe that's not
> the case.
> 
> I still can't understand how this is linked to pps* though.  I tried
> to pull all the sources so I can read through, but my third-world
> internet connection is driving me crazy and I don't know what to do
> with 'git' when a transfer is interrupted.
> 
Note that this is a problem with /dev/pps1 and not /dev/ttyS0, so from
my point of view its NOT a buffer problem on /dev/ttyS0.

Rather, I question whether the /dev/pps1 actually gets built when you
do whatever system call it is to create it, or whether something is just
put on a queue to be done, whenever.

If the latter is the case then we need some sort of lock to not return
till the work is actually done.
-- 
                                        Reg.Clemens
                                        reg at dwf.com