ATZ in enabling_modem_init() step

[Aleksander Morgado]

On 27/07/17 11:15, Tim Small wrote:
>>> I wonder if issuing ATZ is the right thing to do here at all?
>>>
>>> It's trying to reset the modem to a well-known state, but ATZ doesn't do
>>> that - it loads the default user defined profile - which could be
>>> anything that the user or another piece of software has saved with AT&W.
>>>
>> I guess it all depends on the modem in use. Plus, yeah, users may
>> configure the modem in some way that may then not work correctly with
>> ModemManager's logic; we have to live with that I'd say.
> This unfortunately will also persist if the user sells the modem to
> someone else unfortunately, which seems a bit broken, I wonder if AT&F1
> is better if MM provides some sort of user hook to add extra config.
> BTW AT&F1 doesn't erase the custom configuration profiles, it just
> doesn't use them.
> 

ModemManager cannot be a completely generic and configurable thing; we must instead try to keep sane defaults. If the user modifies persistent configuration that makes it incompatible to run with ModemManager for some reason, well, yes, it's unfortunate, but we cannot do much more.

> Apart from this ATZ vs AT&F1 issue, just running which ever one is chose
> once on port open, not after every call would fix the hot-swap issue.
> What are your thoughts on that?
> 

Yes, this is something we can look into. But sim hot swap is really the only thing that is affected; all the runtime configuration happens once the modem is enabled, and the configuration is cleared up when disabled.

-- 
Aleksander
https://aleksander.es