Implement signal strength polling in plugin/driver

Implement signal strength polling in plugin/driver

[Audric Schiltknecht]

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Hi guys,

It seems my first post was lost, so here is a new try.

I am currently developing an ofono-based GSM control interface, using a 
Sagem
Hilo modem (I wrote the appropriate plugin) with the atmodem driver.

I am having trouble with signal strength reporting. The terminal does 
not report
signal strength by event. Hence, it is not possible to get the value 
from Ofono,
since Ofono expects it to be updated on a +CIEV event. I implemented a
new DBus method in the NetworkRegistration interface to force AT+CSQ 
command and
update the property value, but this is clearly not a valid solution.

I found by looking in include/netreg.h that it should be up to the 
plugin to
implement CSQ polling, however I can't find how it is supposed to be 
done.
Indeed, the plugin has no access to the netreg atom nor structure, so 
how is it
supposed to update one of these properties ?

Thank you for your help.

Regards,
Audric Schiltknecht

Re: Implement signal strength polling in plugin/driver

[Denis Kenzior]

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Hi Audric,

> I found by looking in include/netreg.h that it should be up to the
> plugin to
> implement CSQ polling, however I can't find how it is supposed to be done.
> Indeed, the plugin has no access to the netreg atom nor structure, so
> how is it
> supposed to update one of these properties ?

Drivers do not modify DBus properties directly.  Instead you should be 
signaling the change to the core the regular way, via 
ofono_netreg_strength_notify.

If you want to implement periodic signal strength reporting, then use 
g_idle_add_seconds to periodically send the +CSQ query.  Please note 
that doing it this way you'd have to keep track of other states.  For 
example, you might want to stop polling when the registration is lost, etc.

Ideally you should be asking your vendor why the signal strength isn't 
reported properly.

Regards,
-Denis

Re: Implement signal strength polling in plugin/driver

[Guillaume Zajac]

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Hi Audric,

On 07/06/2012 17:20, Audric Schiltknecht wrote:
> Hi guys,
>
> It seems my first post was lost, so here is a new try.
>
> I am currently developing an ofono-based GSM control interface, using 
> a Sagem
> Hilo modem (I wrote the appropriate plugin) with the atmodem driver.
>
> I am having trouble with signal strength reporting. The terminal does 
> not report
> signal strength by event. Hence, it is not possible to get the value 
> from Ofono,
> since Ofono expects it to be updated on a +CIEV event. I implemented a
> new DBus method in the NetworkRegistration interface to force AT+CSQ 
> command and
> update the property value, but this is clearly not a valid solution.

Do you know in modem specifications if Sagem is using a specific signal 
strength notifications command?
If yes, then you should update in drivers/atmodem/network-registration.c 
the at_creg_set_cb() function to handle OFONO_VENDOR_SAGEM case.
Thus you can use register to the good comman notification.

Could you also give us your AT log and more particulary the 
"AT+CMER=3,0,0,1" answer?
Maybe, this configuration is not supported by your modem and you should 
change it.

>
> I found by looking in include/netreg.h that it should be up to the 
> plugin to
> implement CSQ polling, however I can't find how it is supposed to be 
> done.
> Indeed, the plugin has no access to the netreg atom nor structure, so 
> how is it
> supposed to update one of these properties ?

Indeed, if you use it for instance with ConnMan signal strength 
notification won't work or maybe I miss something.

Kind regards,
Guillaume

Re: Implement signal strength polling in plugin/driver

[Audric Schiltknecht]

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Guillaume,

On Mon, 11 Jun 2012 16:00:23 +0200, Guillaume Zajac wrote:
> Hi Audric,
>
> On 07/06/2012 17:20, Audric Schiltknecht wrote:
>> Hi guys,
>>
>>
>> I am currently developing an ofono-based GSM control interface, 
>> using a Sagem
>> Hilo modem (I wrote the appropriate plugin) with the atmodem driver.
>>
>> I am having trouble with signal strength reporting. The terminal 
>> does not report
>> signal strength by event. Hence, it is not possible to get the value 
>> from Ofono,
>> since Ofono expects it to be updated on a +CIEV event. I implemented 
>> a
>> new DBus method in the NetworkRegistration interface to force AT+CSQ 
>> command and
>> update the property value, but this is clearly not a valid solution.
>
> Do you know in modem specifications if Sagem is using a specific
> signal strength notifications command?
> If yes, then you should update in
> drivers/atmodem/network-registration.c the at_creg_set_cb() function
> to handle OFONO_VENDOR_SAGEM case.
> Thus you can use register to the good comman notification.

According to the modem specification, the modem should use a standard 
+CIEV
event to report signal strength.
However, I found that the strength is never notified as expected,
whereas it is correctly returned when using an AT+CSQ read command.
Moreover, the value returned in +CIEV is theoretically an integer in 
the range 0-4,
when AT+CSQ returns a well more fine-grained value (integer between 
0-31).

> Could you also give us your AT log and more particulary the
> "AT+CMER=3,0,0,1" answer?
> Maybe, this configuration is not supported by your modem and you
> should change it.

Indeed, mode 3 is not supported, and I modified the driver to use mode 
1.

>> I found by looking in include/netreg.h that it should be up to the 
>> plugin to
>> implement CSQ polling, however I can't find how it is supposed to be 
>> done.
>> Indeed, the plugin has no access to the netreg atom nor structure, 
>> so how is it
>> supposed to update one of these properties ?
>
> Indeed, if you use it for instance with ConnMan signal strength
> notification won't work or maybe I miss something.

I use my own DBus client, but the effect is the same: no notification 
of signal
strength change, unless I explicitly call the custom function I added 
in src/network.c
to force polling of the strength.

Thanks for your support.
Audric

Re: Implement signal strength polling in plugin/driver

[Audric Schiltknecht]

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Denis,

>> I found by looking in include/netreg.h that it should be up to the
>> plugin to
>> implement CSQ polling, however I can't find how it is supposed to be 
>> done.
>> Indeed, the plugin has no access to the netreg atom nor structure, 
>> so
>> how is it
>> supposed to update one of these properties ?
>
> Drivers do not modify DBus properties directly.  Instead you should
> be signaling the change to the core the regular way, via
> ofono_netreg_strength_notify.
>
> If you want to implement periodic signal strength reporting, then use
> g_idle_add_seconds to periodically send the +CSQ query.  Please note
> that doing it this way you'd have to keep track of other states.  For
> example, you might want to stop polling when the registration is 
> lost,
> etc.

Oh, I see. Indeed, I noticed that signal strength reporting
is stopped when modem is not registered. I'll keep that in mind.
Thank you for the lead on this matter.

>
> Ideally you should be asking your vendor why the signal strength
> isn't reported properly.

Sure, it would be great to not have to do all these hacks to get it 
working right !

Regards,
Audric