Insteon: Attempt to Reconnect PLM if it Appears to be Down

[krkeegan]

• Add flag to track if a message sent to the PLM has been acknowledged by the PLM
• On retry, if no receipt was acknowledged by the PLM, attempt to re-open the PLM serial port

Should fix #397

[rudybrian]

I'm running this now and will report back on what I see.

[rudybrian]

Initial testing with usbreset looks good, and MH recovers correctly. I will continue to run this to see if my MH system's intermittent USB reset issue causes different behavior.

[rudybrian]

It took a while, but my USB PLM finally reset on it's own early this morning. MH correctly detected this, reinitialized the PLM and recovered.

Looks good!

[jsiddall]

Agreed, looks good. Once I figured out how to get git to do what I wanted the code seems to work great.

[krkeegan]

Awesome, thanks for testing this.

[jsiddall]

One thing I have noticed is that there have been a couple of times where nothing immediately came back from a transmit (not sure the root cause of that) and the reconnect code was triggered even though the port had not closed. Nothing bad came of it so I think this is acceptable behavior for now. A future enhancement might be to attempt to contact the PLM itself (not sure if that is feasible) upon suspicion of a port closure to confirm whether the PLM is really gone before re-opening the port.

[krkeegan]

Yeah, I thought that might happen. The bad thing is that we may dump
incoming data by restarting the port.

Not really sure how to check if the port is still open. What I could do is
not reconnect after a single instance of a failure to respond, but instead
require two in a row. That would likely do it.
On Apr 25, 2014 8:58 PM, "jsiddall" notifications@github.com wrote:

One thing I have noticed is that there have been a couple of times where
nothing immediately came back from a transmit (not sure the root cause of
that) and the reconnect code was triggered even though the port had not
closed. Nothing bad came of it so I think this is acceptable behavior for
now. A future enhancement might be to attempt to contact the PLM itself
(not sure if that is feasible) upon suspicion of a port closure to confirm
whether the PLM is really gone before re-opening the port.

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/401#issuecomment-41459142
.

[jsiddall]

I understand what you are saying but failures to a single device aren't a good indicator of port state. Ex: say a breaker has tripped that has an insteon device on it. Transmits to that device will always fail even though there is nothing wrong with the port. Which is why I was thinking a better test is the ability to talk to the PLM itself. I have not looked through the code but something is generating this in the logs on startup:

[Insteon_PLM] PLM id: 24150e firmware: 9b

Which implies it is possible to talk to the PLM without any other Insteon network dependencies. So perhaps whatever code generated that message could be used as a test to see if the PLM is still connected to the port or if it should be re-opened.

[krkeegan]

Oh, sorry, we have a mis-communication. Some technical details:

Whenever MH sends a command, the PLM first confirms receipt of the command,
and then we get a confirmation from a device once that message is received
by the device.

This code doesn't look at the confirmation from the device, but rather
confirmation from the PLM.

In the instance you described, your PLM did not respond to the command.
Now I agree, that maybe a single failure of the PLM to respond shouldn't
cause MH to reopen the port, but to my knowledge there is nothing else we
can do to "test" whether the port is still open rather than just attempt to
send a command to the PLM again.

On Sat, Apr 26, 2014 at 9:37 AM, jsiddall notifications@github.com wrote:

I understand what you are saying but failures to a single device aren't a
good indicator of port state. Ex: say a breaker has tripped that has an
insteon device on it. Transmits to that device will always fail even
though there is nothing wrong with the port. Which is why I was thinking a
better test is the ability to talk to the PLM itself. I have not looked
through the code but something is generating this in the logs on startup:

[Insteon_PLM] PLM id: 24150e firmware: 9b

Which implies it is possible to talk to the PLM without any other Insteon
network dependencies. So perhaps whatever code generated that message could
be used as a test to see if the PLM is still connected to the port or if it
should be re-opened.

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/401#issuecomment-41473444
.

[jsiddall]

OK, I understand. I thought there was no response from the PLM after sending a message while waiting for a response from the module. Given that there is supposed to be some response to a command waiting for a retry after a failed attempt before trying to re-open the port is probably a good idea since it appears sometimes the acknowledgement from the PLM gets lost.