'Signal' interface

[Dan Williams]

On Wed, 2013-07-10 at 10:20 +0200, Aleksander Morgado wrote:
> Hey,
> 
> So I've been thinking in having a new DBus interface for modems which
> support extended signal information reporting. I currently wrote the
> support for a new 'Signal' interface, which exposes things like RSSI,
> EcIo, RSRP, RSRQ... currently only available for QMI-based modems.
> 
> I would like to know what you think of the the new interface. My current
> questions would be:
> 
>  * Is 'Signal' a good name for the interface? I was thinking in adding
> more stuff there, like instant power values of the RX/TX chains. Can't
> think of a more generic name, suggestions welcome.

Name sounds fine to me.

>  * Currently values are provided as independent properties, e.g.
> "gsm_rssi", "umts_rssi"... Another option would have been to provide
> per-technology dictionaries, like a "gsm" property with signature
> "a{sd}" where the string is the parameter (e.g. "rssi") and the double
> is the actual value. Don't have a strong feeling about this.

I think a per-technology/radio dictionary might be a bit cleaner, since
then you don't need the 'valid' booleans, since the dict would only
include those items that were valid.  Also, we could potentially include
statistics on power control, gain control, noise, frame error rate,
sensitivity, etc, and those are all per-radio too.  I think a non-dict
interface might be a pain to keep updating if we add further stats in
the future.

What do you think?

Dan

>  * By default, retrieving extended signal information is disabled
> (rate=0); the user needs to explicitly enable it by providing a rate>0
> in Setup().
> 
> The current implementation is available in the
> 'aleksander/signal-interface' branch upstream, and also has new mmcli
> commands to test it:
> 
> Setup extended signal information retrieval to be refreshed every 5s:
>  $> sudo mmcli -m 0 --signal-setup=5
> 
> Then, get all values:
>  $> sudo mmcli -m 0 --signal-get
> 
> Also, the retrieval will be done *only* when the modem is enabled.
> 
> You can also take a look at the interface itself directly here:
> 
> http://cgit.freedesktop.org/ModemManager/ModemManager/tree/introspection/org.freedesktop.ModemManager1.Modem.Signal.xml?h=aleksander/signal-interface
> 
> Comments welcome!
>