Should the HAVE_KERNEL_PLL conditional be abolished?
hmurray at megapathdsl.net
Sun Dec 3 20:21:19 UTC 2017
> Should the HAVE_KERNEL_PLL conditional be abolished? Or. to put it
> equivalently, do we have any development targets that lack ntp_adjtime()/
That symbol is not defined when I build on OpenBSD.
I'd be happy to clean up that area, but I think it is more complicated than
you have indicated.
There are 2 RFCs
RFC1589: Kernel Model for Precision Timekeeping
RFC2783: Pulse-Per-Second API
There are actually two interesting parts to that tangle.
The first is getting timing data for a pulse. PPS for NTP is the main use,
but it can also be used for general hacking. (I use it to monitor the power
The second is a PLL inside the kernel that gets switched on if you set a bit.
That works significantly better than whatever ntpd does. I think we should
be able to fix this. It's not a trivial fix. It may require implementing
the wake-on-data-ready option which doesn't seem to be implemented. (but
maybe I didn't look in the right place)
The "HAVE_KERNEL_PLL" is used for both of them even though there is nothing
PLL related to the first usage.
These are my opinions. I hate spam.
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