Re: [gpsd-dev] Detecting Raspberry Pi Hat & PPS

[Gary E. Miller]

Yo Frank!

On Thu, 5 May 2016 20:49:11 -0400
Frank Nicholas <address@hidden> wrote:

> From my Pi2:
> dev2-rpi ~ # gpsd -nND 9 /dev/ttyAMA0 |& fgrep PPS
> gpsd:PROG: PPS:/dev/ttyAMA0 chrony socket /var/run/chrony.ttyAMA0.sock 
> doesn't exist
> gpsd:WARN: KPPS:/dev/pps0 kernel PPS unavailable, PPS accuracy will suffer

Ouch.  gpsd tried to open the /dev/pps0 because you had
the /dev/ttyAMA0.  Good so far, but...

We have seen this before, the solution unclear.  Look in: ppsthread.c.
Basically init_kernel_pps() failed.  Either it could not open(/dev/pps0)
or it could not time_pps_create() that file handle.

Probably not the former, since you did not see:
    "KPPS:%s running as %d/%d, cannot open %s: %s\n",

Probably not the laster, since you did not see:
    "KPPS:%s time_pps_create(%d) failed: %s\n"

I am blind to what other failure path is in there without an error
log.

> PPS device is automatically created:
> crw-rw---- 1 root tty  244, 0 Dec 31  1969 /dev/pps0

I assume 'ppstest /dev/pps0' works fine?

You might try perms 666 to rule out a permissions problem.  That has
not helped before.

> Stock Raspberry Pi kernel from:
> git clone --depth 1 https://github.com/raspberrypi/firmware.git

> pps_gpio                2655  0
> pps_core                6779  1 pps_gpio

Those are the two you need.  Thus the /dev/pps0.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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