u-blox TOBY-R200 Intermittent Long Registration on Simple Connect

[Dan Williams]

On Mon, 2018-04-30 at 20:09 +0000, Matthew Starr wrote:
> > -----Original Message-----
> > From: Aleksander Morgado [mailto:aleksander at aleksander.es]
> > 
> > > 
> > > I don't understand why there is a 20 second timeout.  Couldn't
> > > you just test
> > 
> > the AT interface right away with 'AT' instead of waiting a timeout
> > and then
> > trying it.  Also 20 seconds is a long time.  Couldn't a much
> > shorter timeout be
> > put in with some message sent to the modem to get it to respond
> > (like 'AT')
> > and do that several times to add up to 20 seconds.  This seems like
> > it would
> > be much quicker in cases where the modem did not respond
> > immediately
> > and might resolve this issue.
> > > 
> > 
> > That 20s timeout is really an artifact added for the TOBY-L4, to
> > wait
> > for the +READY URC it sends if the port is detected via hotplug
> > events. It's actually just to make it quicker the probing in the
> > TOBY-L4. This should be therefore something specific for the TOBY-
> > L4
> > and not something generic for all u-blox modems... sorry for that
> > :/
> > 
> > I'll gladly accept a patch that makes this 20s timeout something
> > specific for the TOBY-L4 ;)
> 
> I changed that timeout to 2 seconds and it resolved the 20 second
> timeout I was seeing.  Now as you said it needs to be something
> specific for the TOBY-L4.  At this early of a point in registration
> you haven't read the model number yet since communication hasn't been
> established.  The only way I can think of detecting the TOBY-L4 is
> using the USB product ID.
> 
> Is there a function that allows obtaining the USB product ID that can
> be used in the context of the wait_for_ready() function in the
> plugins/ublox/mm-plugin-ublox.c file?  I tried the
> mm_port_probe_get_product() function called within the
> wait_for_ready() function, but just got (null) returned.
> 
> Do you know if the TOBY-L4 has a unique USB product ID?  If so, do
> you know what it is?

Could do it through udev tags too; eg tag TOBY-L4 in the udev rules as
needing a larger timeout, but all the rest get a shorter one.

Dan