SARA-R410M-52B, 'Connection request forbidden: operation already in progress'

[Aleksander Morgado]

Hey!

> I'm trying to help a customer through an issue she's having with the SARA-R410M-52B.  I have--for the most part--exhausted my troubleshooting abilities, and am hoping for some insight.  (To my knowledge) I have tested the same configuration with my own hardware at my location and everything works flawlessly.
>
> A basic overview of what's occurring is when she tries to "--simple-connect" the timeout is reached, then she receives an error message:
>
>> root at bionic-ventana:~# mmcli -m 0 --simple-connect="apn=hologram"
>> error: couldn't connect the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.InProgress: Connection request forbidden: operation already in progress'
>
>
> I had her try different SIM's, also checked that she could scan for networks.  Scan appears to be working correctly:
>
>> root at bionic-armhf:~# mmcli --modem 0 --3gpp-scan --timeout=300
>>   ---------------------
>>   3GPP scan | networks: 311480 - 311 480 (lte, available)
>>             |           310410 - 310 410 (lte, available)
>>             |           310260 - T-Mobile (lte, current)
>>             |           311480 - 311 480 (lte, available)
>
>
> Here's a bit more output to characterise the error:
>
>> root at bionic-ventana:~# mmcli -m 0
>>   --------------------------------
>>   General  |            dbus path: /org/freedesktop/ModemManager1/Modem/0
>>            |            device id: 070da71645456ab4f79b820d7ffc7e36db96ff80
>>   --------------------------------
>>   Hardware |         manufacturer: u-blox
>>            |                model: SARA-R410M-52B
>>            |    firmware revision: L0.0.00.00.06.08  1  [Apr 11 2019 18:01:44]
>>            |       carrier config: default
>>            |         h/w revision: 10000
>>            |            supported: lte
>>            |              current: lte
>>            |         equipment id: 357812093841846
>>   --------------------------------
>>   System   |               device: /sys/devices/soc0/soc/2100000.aips-bus/2184200.usb/ci_hdrc.1/usb2/2-1/2-1.2/2-1.2.3
>>            |              drivers: qmi_wwan, option1
>>            |               plugin: Generic
>>            |         primary port: cdc-wdm0
>>            |                ports: ttyUSB0 (qcdm), ttyUSB1 (at), cdc-wdm0 (qmi), wwan0 (net)
>>   --------------------------------
>>   Status   |                 lock: sim-pin2
>>            |       unlock retries: sim-pin (3), sim-pin2 (10), sim-puk (10), sim-puk2 (10)
>>            |                state: enabled
>>            |          power state: on
>>            |       signal quality: 0% (cached)
>>   --------------------------------
>>   Modes    |            supported: allowed: 4g; preferred: none
>>            |              current: allowed: 4g; preferred: none
>>   --------------------------------
>>   Bands    |            supported: eutran-1, eutran-2, eutran-3, eutran-4, eutran-5, eutran-8,
>>            |                       eutran-12, eutran-13, eutran-17, eutran-18, eutran-19, eutran-20,
>>            |                       eutran-26, eutran-28, eutran-39
>>            |              current: eutran-1, eutran-2, eutran-3, eutran-4, eutran-5, eutran-8,
>>            |                       eutran-12, eutran-13, eutran-17, eutran-18, eutran-19, eutran-20,
>>            |                       eutran-26, eutran-28, eutran-39
>>   --------------------------------
>>   IP       |            supported: ipv4, ipv6, ipv4v6
>>   --------------------------------
>>   3GPP     |                 imei: 357812093841846
>>            |         registration: idle
>>   --------------------------------
>>   3GPP EPS | ue mode of operation: csps-2
>>   --------------------------------
>>   SIM      |            dbus path: /org/freedesktop/ModemManager1/SIM/0
>> root at bionic-ventana:~# mmcli -m 0 --enable
>> successfully enabled the modem
>> root at bionic-ventana:~# mmcli -m 0 --simple-connect="apn=hologram"
>> error: couldn't connect the modem: 'Timeout was reached'
>> root at bionic-ventana:~# mmcli -m 0 --simple-connect="apn=hologram"
>> error: couldn't connect the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.InProgress: Connection request forbidden: operation already in progress'
>> root at bionic-ventana:~# mmcli -m 0 --simple-connect="apn=hologram"
>> error: couldn't connect the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.InProgress: Connection request forbidden: operation already in progress'
>

It seems the modem never gets registered in the network, and even
signal quality is reporting as 0%. If you're sure that the SIM is the
correct one, it may be wise to recheck hardware connection of the
antenna (if there is an external one).

The problem with the --simple-connect is a side effect of not being
registered. The first phase of the simple connect sequence is making
sure the modem is registered in the network, and if there's no signal,
that will take a lot of time. Now, unless explicitly specified a
longer timeout for the mmcli request (with --timeout=N) then the
default DBus timeout of 30s applies. This means that if the simple
connect doesn't return a response in 30s, the request will timeout in
the mmcli side. You should update your  mmcli --simple-connect command
to use e.g. --timeout=300 or something like that, and you should at
least avoid the timeout error.

The next "operation already in progress" errors are because there is
already a simple connect ongoing in the daemon, even if the request
timed out in the client. Only once that background simple connect
finishes you will be able to re-run --simple-connect attempts again.

But none of your --simple-connect attempts will work until the modem
gets registered in the network.

-- 
Aleksander
https://aleksander.es