Hi Caiwen,

Please don't top-post on this list.  Thanks for your understanding.

Now as to your question:

 >
> In fact I have ever considered the way you mentioned. But l found in most plugins, atoms (gprs, gprs_context, sms,
> call_forwarding ...) are created at post_sim phrase. It seems post_online phrase is more reasonable. There should
> be some reason that the atom creation is brought forward. Does anyone know the reason?
>

It really depends on what the particular atom supports and what the 
hardware supports.  The modem driver has some leeway to place atoms in 
the appropriate state callback (.pre_sim, .post_sim, .post_online).

Generally, anything that accesses the SIM can safely go into .post_sim 
if the hardware supports this mode properly, e.g. sim on, rx/tx radio 
circuits off.  sim and gprs atoms also support being in post_sim.  This 
is done so that settings can be tweaked while offline.

In the case of the rilmodem gprs driver, the querying of max_cids is 
needed in order to tell oFono core the id range.  This operation needs 
to be done once before the atom is registered.  If this operation is not 
available on the RIL in 'post_sim' (not online) state, then it is  safer 
to move the gprs atom into post_online callback than trying to follow 
radio state changes and (repeatedly) query max_cids.

If you really need gprs to be in post_sim, then we can discuss some 
alternative solutions.

Regards,
-Denis