[gpsd-dev] Please review Miroslav's attempted fix.

[Eric S. Raymond]

Live-testing PPS on the GR-601W I found it broken.  The reason quickly
became aopparent; there was a May 27 commit by Miroslav Lichvar that
landed way, way out of sequence and stepped on something.

Reverting it, I now have PPS live on the GR-601W again.

However...Miroslav generally knows what he's doing. I think it would
be unwise to write off the possibility that he was fixing a real bug.
Here's his comment:

commit 0a3ca7297044d71cf743e6b975a47f16810bf071f
Author: Miroslav Lichvar <address@hidden>
Date:   Tue May 27 18:37:02 2014 +0200

    Fix PPS with large offsets.

    This was broken by commit 575444. The check if the PPS time isn't
    referenced with an old message time used PPS offset instead of the
    difference between local PPS time and local time of the last message.
    The PPS sample was reported via SHM or chrony socket only if the offset
    was between -1 and 1000001 seconds.

    Keep the local timestamp of the last fix in struct gps_device_t in
    addition to the real timestamp and use it to check the PPS delay.
    Rename the l_offset variable to delay to avoid further confusion.

Please review his commit to see if there's something that needs to
be salvaged from it.  Also relevant is:

commit a006eef564b7a6bab2c8568d54fadff20ff59365
Author: Eric S. Raymond <address@hidden>
Date:   Thu Aug 21 18:30:23 2014 -0400

    Restore PPS function by backing out Miroslav Lichtvar's last commit.
    
    It came in way, way out of sequence ansd screwed something up.  He may
    have been fixing some real problem, however.  This requures
    investigation.
    
    All regression tests pass.

Miroslav, if you're listening and can look into this yourself, please
speak up.

Also please note that I prefer people not use git hashes in change
comments. They'll become meaningless if the project ever has to change
VCSes again.  Better to refer by committer and date.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>

The conclusion is thus inescapable that the history, concept, and 
wording of the second amendment to the Constitution of the United 
States, as well as its interpretation by every major commentator and 
court in the first half-century after its ratification, indicates 
that what is protected is an individual right of a private citizen 
to own and carry firearms in a peaceful manner.
         -- Report of the Subcommittee On The Constitution of the Committee On 
            The Judiciary, United States Senate, 97th Congress, second session 
            (February, 1982), SuDoc# Y4.J 89/2: Ar 5/5