[LinuxPPS] linuxpps-v5.3.2 is missing ioctl32 compatibility

[George Spelvin]

"Cirilo Bernardo" <cirilo.bernardo at gmail.com> wrote:
> There has been some discussion before that a possible execution path
> within ntpd may set the line discipline back to N_TTY (or perhaps the
> request to change the line discipline is not handled correctly by the
> serial driver?)

I thought it was just the multiple calls to time_pps_setparams() was confusing the
kernel somehow.

> I don't see a point in being able to use both CAPTUREASSERT and
> CAPTURECLEAR - usually only one of these provides a reliable timing
> reference and the other will have a (usually) unspecified jitter.
> Also, if the association is on a per-file descriptor basis, how do we
> make the selection without trying to push more changes through NTPD?

Well, the PPS API provides it, so I think it's useful.  And it lets you
run ppstest while ntpd is running without screwing it up.

As for how you make the selection, ntpd already makes the selection based
on flag2 in ntp.conf.

See ntpd/refclock_atom.c:atom_control():
	if (pp->sloppyclockflag & CLK_FLAG2)
		mode = PPS_CAPTURECLEAR;
	else
		mode = PPS_CAPTUREASSERT;