[LinuxPPS] unofficial Test patch for linux v2.6.30-rc6

[William S. Brasher]

On Wed, 20 May 2009, Udo van den Heuvel wrote:

> William S. Brasher wrote:
> > I have installed kernel 2.6.30-rc6 patched with ntp-pps-v2.6.30-rc5 
> 
> I.e.: the patch that Rodolfo posted here.
> 
> > and pps seems to be working fine with ntp-4.2.4p7 and glibc-2.9.
> > 
> > 
> > The first time I ran ppsldisc I got the following in the logs:
> 
> Hmm. Are you sure ppsldisc, etc were compiled with the same code as the patch?
> (I mean, ppsldisc was not lying around from a previous release?)
> 
> This WARNING thingie did not reappear? And if you reboot?
> Maybe just use `ldattach 18 /dev/ttyS0` instead to see if the ppsldisc or
> LinuxPPS code is at fault?
> 
> 
> Udo
> 
> 


The programs ppsldisc et al were compiled in the Document/pps directory 
after the kernel had been built.  The only header in /usr/include/linux 
from this new kernel was /usr/include/linux/pps.h; the rest of the kernel 
headers in /usr/include came from linux-2.6.28.9.  I also moved a copy of 
timepps.h from Documentation/pps to /usr/include.

Finally, I modified  include/linux/timex.h in the kernel source to change 
SHIFT_PLL from 4 to 2. 

The new, patched ntp-4.2.4p7 was also built with the new headers in place.


The first time I booted the new kernel and started ppsldisc I received 
that warning in the logs.  I have rebooted  that machine since then and 
both pps and ntp started on boot, and did not generate any warnings.

That is actually a lot better that previous versions of the patch:  for 
some reason I've been unable to uncover, yet, ntp/pps tends to hang on my 
machines and require manual operator intervention to get started.  That 
would appear to be a problem with ntp-4.2.4p6, since I've had the same 
problem with 2.4 kernels.


On the last boot pps and ntp started 'automatically' and within 30 minutes 
ntpq -d reported:

     remote   refid      st t when poll reach   delay  offset  jitter
======================================================================
+GPS_NMEA(0)  .GPS.       0 l   12   16  377    0.000  0.000  0.002
oPPS(0)       .PPS.       0 l    2   16  377    0.000  0.000  0.002