On 19/11/2012 09:44, Miroslav Lichvar wrote:
On Mon, Nov 19, 2012 at 09:02:12AM +0000, David Taylor wrote:
On 18/11/2012 15:20, Uwe Klein wrote:
what happens if you "insmod pps_ldisc" into the "not ready" system?
(1) I get Error: could not load pps_ldisc module: No such file or directory
insmod needs full path to the module, it's better to call "modprobe pps_ldisc".
I looked at the article you referenced, but in this case the
Raspberry Pi is not using the DCD line, but a separate GPIO pin.
lsmod shows pps_gpio as present.
From the original post it seems you have two pps devices, one for gpio
and the other for ldisc which is created two minutes later (some USB
device?).
Do you see two /dev/pps* devices and are you sure ntpd is using the
gpio one? Perhaps there is an ordering problem?
Your help is much appreciated, folks!
On both systems, sudo modprobe pps_ldisc produces no output.
I have no idea which device ntpd is using, I simply have the type 22
driver installed which, as I understood it, gets the accurate timestamp
from the kernel. How the kernel chooses which device to use I don't know.
In /dev I see pps0 on the system without a PPS signal connected, and
pps0 and pps1 on the system /with/ the PPS signal active. On the system
/with/ the signal active, some 25 seconds in the dmes output I see:
pps_ldisc registered (so ldisc does matter, I stand corrected), followed
by pps1 new source, and source /dev/ttyAMA0 added.
So the issue appears to be that /dev/ttyAMA0 is not created until the
GPS receiver is sending second pulses, and by that time ntpd is running
and can't see the device. Here are my lines from ntp.conf:
# Kernel-mode PPS ref-clock for the precise seconds
server 127.127.22.0 minpoll 4 maxpoll 4
fudge 127.127.22.0 flag3 1 refid PPS
I wonder whether I should be using 127.127.22.1 rather than .0?
--
Cheers,
David
Web: http://www.satsignal.eu
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