Using AT+CFUN=7 (if supported) to switch into offline mode has a problem
with older modems. Sending AT+CFUN=7 with a data connection active has
the problem that it never terminates with OK or ERROR.
Devices that support AT^RFSWITCH are known to handle this properly. So
only when that command is supported, use AT+CFUN=7 for offline mode. If
it is not supported, then keep using AT+CFUN=5 to switch the device into
offline mode.
When switching from offline into online mode, the SIM card access
gets temporarily disabled by the modem firmware. To work around
this limitation poll the SIM card state.
huawei_disconnect is used to recovery the io and gprs context when
io error happends, see commit 39382730d7
However, io error not only happends at PPP disconnect, in theory it
can happends at any situation. I also observed that it happens when modem
go into offline mode at my Huawei EM770W modem. in this case, gprs should
not be reopened.
Sim state is already known after modem is enabled and there's no need to
query it again. Before this patch, query_sim_state() was called upon
huawei_enable() and huawei_pre_sim(). Both functions might call
notify_sim_state() with a valid state. Hence we could eventually end up
sending AT+CFUN=5 command twice.
If a "^SYSINFO" arrives after the timer for query_sim_locked() has been
set up, it'd would set a new timer, signaling a sim state change more
than once.
When SIM is locked, huawei modem does not send any notification about
SIM state change because it does not differentiate 'invalid' from
'locked'.
In order to be able to unlock the sim, this patch forces a notification
of a valid state after a timeout.
This patch was generated by the following semantic patch
(http://coccinelle.lip6.fr/)
// <smpl>
@fix disable is_null,isnt_null1@
expression *E;
@@
- !E
+ E == NULL
// </smpl>
The recently introduced online support to huawei didn't work with my
Huawei E1552. The problem was that with command AT+CFUN=1;+CFUN=5
the modem didn't initialise the sim state properly.
To fix this I changed the logic so that CFUN=5 is called only after the sim
state has switched to a valid state. Now my Huawei E1552 works with connman
again.
PIN locked SIMs still won't work. The problem is that it takes some time for
the sim state to go to a valid state:
Sep 20 15:01:57 dell-m520 ofonod[12451]: Pcui:< \r\n+CPIN: READY\r\n\r\nOK\r\n
[...]
Sep 20 15:02:00 dell-m520 ofonod[12451]: huawei: invalid sim state in post online (0)
[...]
Sep 20 15:02:01 dell-m520 ofonod[12451]: Pcui:< \r\n^SIMST:1\r\n
I don't know why it takes so long to get a valid state.
There is also another issue, in "cold start" case the phonebook
initialisation fails:
Sep 20 14:34:24 dell-m520 ofonod[11939]: Pcui:> AT+CPBS=?\r
Sep 20 14:34:24 dell-m520 ofonod[11939]: Pcui:< \r\n+CME ERROR: SIM busy\r\n
But in "warm start" it seems to work:
Sep 20 14:38:59 dell-m520 ofonod[12091]: Pcui:> AT+CPBS=?\r
Sep 20 14:38:59 dell-m520 ofonod[12091]: Pcui:< \r\n+CPBS: ("SM","EN","ON")\r\n\r\nOK\r\n
I consider this as a minor issue and didn't investigate it at all.
On my Huawei E1552 when I plug in the modem (ie. cold start) with PIN locked
SIM, the sim state is 255 (HUAWEI_SIM_STATE_NOT_EXISTENT). As the modem
doesn't send ^SIMST notifications, poll the sim state until it's ready.
In theory it might be possible to do this better, for example follow
^BOOT notifications or something, but it's unknown what parameter we
should check for.