2009/8/10 Denis Kenzior <denkenz(a)gmail.com>:
> It would make sense for the providers to resend the MWI
> everytime subscriber connects the network and then it would be less
> problematic in case the information couldn't be written to SIM, but I
> don't know if they ever do this.
Probably they don't, there are also weird roaming cases to consider, where you
receive MWI, turn phone off, step on a plane and turn phone on with some other
There is another case to consider when the SIM is moved to a
completely different phone. In fact, I think this is the original
reason to store the MWI flag to the SIM.
Can we make the MWI interface smarter somehow? Perhaps by not
unless at least the EFmwis file is available, or by always storing the EFmwis
contents on the filesystem?
I think this makes sense. There is another, related issue with some
Nokia modems, though. They might not support low-level, EF access
directly, but have some higher level API for accessing things like the
MWI flag, HPLMN list and SPN. We might need to think about adding such
high-level API support to the driver API as (optional) ops --
especially if other modems behave similarly -- otherwise the ISI modem
driver may need some kluge to handing EF writes.