On Wed, Dec 11, 2013 at 10:11:48AM -0800, Bill Unruh wrote: > On Wed, 11 Dec 2013, Miroslav Lichvar wrote: > >When no source is selected, the PPS samples are ignored. If the SHM > >source doesn't move to the acceptable range to overlap with the PPS > >source in 8 polling intervals, the PPS source is marked as unreachable > >and the SHM source is selected as the only available source. > > That sounds like a bug. PPS should always be part of the selection process. It > is almost by definition the correct source. And certainly it could be argued > that the PPS should be the selected source, not the nmea. Of course some > people (me) us shm to deliver pps to chrony, so shm should not automatically > be downgraded, but a kernel pps it seems certainly should not be downgraded.
I think it works as expected. When there is a PPS source and a SHM source and they don't agree, what do you do? Pick the PPS source only because it's from the PPS driver? The SHM source can be from a PPS signal too (as is in your case). If it was configured with the prefer flag, I'd probably agree. > >The configured delay is included in the interval used in the source > >selection algorithm, so increasing the value from 0.01 to 0.4 or > >larger should fix the problem. > > A user should not have to do this or know this. That would be nice, but I'm not sure how should chrony detect that the source is a falseticker without comparing it to other sources. The recommended configuration is to mark such sources with noselect and use them only for PPS locking. -- Miroslav Lichvar -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
