Signal quality not updated with Quectel EG25 through QMI

[Aleksander Morgado]

Hey,

>
> > But what do you want? Do you want the extended signal interface
> > information, or do you want the percentage value (which is probably
> > what you were using when AT protocol was being used).
>
> I want the percentage value for the moment (to keep backward compatibility with what we got when using ppp). But I'll look at extended signal interface in the future
>

Ok.

> > Have you done tests e.g.
> > disconnecting antennas and such, to see if those indications are
> > emitted?
>
> Nope, I didn't test that (and I don't know how)
>

While you have debug logs on, you could physically disconnect the
antenna from the modem. It's a EG25, I assume in miniPCIe format? Do
you have access to the antenna connectors?

> > If possible, please debug that with MM debug level
> > enabled and also with the qmi-proxy running in verbose mode (in case
> > the problem is a failure in the indication forward done by the proxy).
>
> Sure, I joined the full log of ModemManager but I didn't find how to make qmi-proxy verbose so I patch https://gitlab.freedesktop.org/mobile-broadband/libqmi/-/blob/1.28.8/src/qmi-proxy/qmi-proxy.c to set verbose_flag to TRUE
> src/qmi-proxy/qmi-proxy.c · 1.28.8 · Mobile broadband connectivity / libqmi
> QMI modem protocol helper library
> gitlab.freedesktop.org

See https://modemmanager.org/docs/modemmanager/debugging/#qmi-proxy-or-mbim-proxy-debug-logs

> From what I see in the log, there is no Signal indications, just a few "Get Packet Statistics"

That may very well be because the signal didn't change too much; i.e.
it stayed in the ranges defined for which we want signal indication
updates. I've reviewed the log, and found that the thresholds given
are very wrong I think:

                                                        <<<<<< TLV:
                                                        <<<<<<   type
     = "Signal Strength Indicator" (0x10)
                                                        <<<<<<   length     = 7
                                                        <<<<<<   value
     = 01:05:B0:D8:00:28:50
                                                        <<<<<<
translated = [ report = 'yes' thresholds = '{ [0] = '-80 ' [1] = '-40
' [2] = '0 ' [3] = '40 ' [4] = '80 '}' ]

The signal strength indicator allows configuring thresholds in the
-127,+127 range (dBm), with a minimum of 5; but that doesn't mean we
should evenly distribute the thresholds in that range. The docs don't
say anything about this being RSSI, but I would have assumed it is,
and in normal user setups we definitely don't expect any RSSI above 0!
Could you edit mm-broadband-modem-qmi.c, method
common_enable_disable_unsolicited_events_signal_strength(), and update
the array of thresholds like this?

    static const gint8 thresholds_data[] = { -110, -100, -90, -80, -70 };

Variations in the antenna connection done manually should definitely
trigger QMI indications reporting the signal quality updates if those
thresholds are configured.

P.D. it's probably time we start integrating the "newest QMI commands"
support by default.

-- 
Aleksander
https://aleksander.es