[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: ✘NMEA2000 and issue #176
From: |
Gary E. Miller |
Subject: |
Re: ✘NMEA2000 and issue #176 |
Date: |
Mon, 21 Feb 2022 10:57:45 -0800 |
Yo James!
My response is in issue #176.
On Mon, 21 Feb 2022 09:23:49 -0800
James Browning <jamesb.fe80@gmail.com> wrote:
> On Fri, Feb 18, 2022 at 7:59 PM Gary E. Miller <gem@rellim.com> wrote:
> >
> > Yo All!
> >
> > I looked at tests/test_nmea2000 again.
> >
> > The good news: adding the -t flag to canplay runs the regression
> > test in 4 seconds instead of almost 4 minutes.
> >
> > The bad news: results from test_nmea2000 are not repeatable...
> >
> > Worse news: When I run the two badly named examples from #176 using
> > test_nmea2000, there is no output at all from either one. Naming
> > canbus data capture files as nmea*.log was very confusing.
> >
> > The NMEA 2000 code in gposd has been broken a long time. Unlikely
> > this gets fixed before the next release.
>
> I think there should be some changes to gpsd to somewhat better
> help NMEA200, CAN bus, CAN over ethernet, etc.
>
> 1. Some {,re}{c,m}allocs, I would suggest that allocating memory to
> device structures at run time rather than build time would allow
> greater flexibility. Initially, I would suggest a single
> scalable allocation at startup.
> 2. CAN-centric protocols are packet-oriented and have at least
> the possibility of packet fragmentation. In this case, you could
> either add to a backing store or throw things away, and I know
> not what is discarded.
> 3. The current NMEA2000://{,v}can* CAN address only maps to a
> single device on the bus, which is only a good thing if there
> are only two devices on the bus. I would suggest dropping the
> first device to having a sub device number, and either having
> the common act as either a promiscuous or NetLink type listener
> (preference for the latter), possibly both.
> 4. Alow for smaller fragmentary reports for the things
> supported.
> 5. Using machine-generated parsers tagged as experimental.
> 6. Get access to Hardware (or at least captures) and/or people
> who can help.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin
pgpzaZUMlk5Bq.pgp
Description: OpenPGP digital signature