Some devices won't get to the initialization stage where we send
CMEE=1 (for numeric error codes) before they return some errors,
so handle the string representation of CME error codes too.
Clients can check the property to determine lock/unlock status and thus
unlock the modem before trying to connect if required.
Bits of the patch by dcbw (see the bug).
Some cards (Novatel S720 for example) can take a long time to start
a data call if the device isn't activated on the network or the
signal strength is low.
Some modems key the AT+CSS? response off their 1X state, so if the
modem has EVDO service but no 1X service, AT+CSS? will provide incorrect
registration state information and the registration checking will
end too early. Allow modems that can handle more specific registration
checking to skip the AT+CSS? part.
There are more places to handle, but these are the most critical. If
the modem is removed while a command is in-progress, the mm-callback-info
code will set info->modem to NULL. Make sure we check for that in
callbacks and return a reasonable error. Previous code would just
blindly forge ahead and die on a null dereference.
Some devices (ZTE MF628) respond to everything except CPIN? with
ERROR unless the PIN has been sent. Since no known CDMA devices
support AT+CPIN, assume that devices that return a CPIN response
are GSM devices.
MM would appear to hang sometimes when writing to serial devices but
in reality was just retrying the write too many times. Make the
retry limit time-based so MM doesn't hang but times the attempt out
instead.
This implements the same fixes that NetworkManager's 0.7 branch
implemented in commits f38ad328acfdc6ce29dd1380602c546b064161ae and
1235f71b20c92cded4abd976ccc5010649aae1a0. Many ZTE devices will
spam the port with messages about waiting voicemail/SMS which buffer
up and cause the device to eventually crash if not suppressed.
at!pcstate is what Sierra CDMA modems use instead of AT+CFUN for
powering the radio on and off. It doesn't turn the modem off completely
like AT+CFUN=0 does for many GSM devices though, so it's quite a lot nicer.
Most AT command references allow modems to report SID 0, even though
SID 0 is not a valid SID and is not assigned to any CDMA network.
Some Sierra 5725 cards have been seen to report valid class and band
from the +CSS response but a SID 0. Accept SID 0 when at least one
other element of the +CSS response indicates that the modem has service.
Otherwise, report "no service" as before.
We only want to ignore connected/connecting/disconnecting states
and update the state based on registration for unsolicited
registration changes. Basically, when disconnecting, the modem
will be in DISCONNECTING state, but after the disconnect has finished
we want to update the modem's state based on the current
registration status. But the previous check for >= DISCONNECTING
would prevent that from happening, so we need a slightly more specific
check in update_enabled_state().
Have to fall back to the previous state if the enable/disable
operation fails since we cannot assume anything about the new
modem state when a failure occurs.
