No data connection switching from 2G only to 3G

[Víctor R. Ruiz]

Test case.
- Open System Settings.
- Go to Cellular.
- Switch from 3G to 2G, check that indicator network shows 2G only connection.
- Switch from 2G only to 3G.

Expected result.
- Indicator network shows 3G connection, and user can use data connection.

Actual result.
- Data connection is lost.

Tested in single SIM and dual SIM mode, with two different SIM cards from different operators.

current build number: 23
device name: krillin
channel: ubuntu-touch/rc-proposed/bq-aquaris.en

[Víctor R. Ruiz (vrruiz)]

After waiting ~10 minutes, connection was up again. May be a duplicate of bug https://bugs.launchpad.net/canonical-devices-system-image/+bug/1418077

[Víctor R. Ruiz (vrruiz)]

I used Movistar and Yoigo SIM cards.

[Víctor R. Ruiz (vrruiz)]

Output of 'list-modems' and 'list-contexts': http://paste.ubuntu.com/11545969/

[Tony Espy (awe)]

@Victor

Could you please reproduce and attach the system directly ( ie. not via past.ubuntu.com )?

[Tony Espy (awe)]

Victor's list-modems output shows the modem registered to Yoigo ( mcc/mnc: 214/04 ), and the RadioSettings TechnologyPreference property set to "umts" ( 3g ). None of the contexts are active, which means NetworkManager has probably disabled the connection due to the autoconnect_retry limit being hit. I can't be sure till I see the syslog though...

[Tony Espy (awe)]

Thanks for the log @Victor.

So the smoking gun is:

Jun 4 14:26:41 ubuntu-phablet NetworkManager[1408]: <info> Disabling autoconnect for connection '/214040113340577/context2'.

There's only one of these in the log. When this happens, NetworkManager has seen a disconnect for the modem, but hasn't yet seen the signal that the GPRS has de-tached ( which is what should happen when you change radio technology ). In this case, NM retries the modem rapidly, and burns through the autoconnect_retry_count for the connection. When this count reaches zero, NM sets a 5m timer to reset the retry_count and try again.

This is indeed similar to the bug #1418077 ( FixReleased ) and bug #1445080 ( InProgress). I have a partial fix for the latter bug which may resolve your specific scenario.

One question, do you wait for the network-indicator to show the mobile connection is active before switching the radio technology from 3g to 2g, and back again? I see the connection coming up in the syslog, but it looks like the technology gets toggled again before it's completely finished.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Víctor R. Ruiz (vrruiz)]

Tony: From 3G to 2G, the data connection is up in a short time. I wait until 2G data is up, and then switch from 2G to 3G. That forces to wait ~10 minutes.

[Pat McGowan (pat-mcgowan)]

We will poke in a fix for this

[Tony Espy (awe)]

I've split out some of the code I was working on for bug #1445080 ( Cellular connection isn't restored after FlightMode disabled ) and created a proposed fix..

I've pushed a test version to my PPA for testing before I go ahead and create a silo ( I'd like the merge proposal reviewed as well ). You can just grab the network-manager and libnm-util2 packages from the PPA and install directly ( install libnm-util2 *before* the network-manager packages ):

https://launchpad.net/~awe/+archive/ubuntu/ppa/+packages

[Tony Espy (awe)]

A couple of minor comments were addressed in the merge proposal, and a new version with an official version number has been pushed to the telephony PPA, this package will be binary sync'd to a silo for landing in the overlay PPA. I will post silo details when they become available.

[Tony Espy (awe)]

For anyone else wanted to test, this fix has landed in silo-031:

https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/landing-031

[Łukasz Zemczak (sil2100)]

This bug was fixed in the package network-manager 0.9.10.0-4ubuntu15.1.2 in https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/stable-phone-overlay

---------------

network-manager (0.9.10.0-4ubuntu15.1.2) vivid; urgency=medium

  * debian/patches/lp1461593-add-modem-reconnect-delay.patch: add
    a 5s delay to NM_POLICY's activation logic triggered when a
    device is disconnected. This allows the modem time to settle
    and NM to process the resulting DBus state changes (LP: #1461593).

 -- Tony Espy <email address hidden> Mon, 08 Jun 2015 15:49:56 -0400

[Launchpad Janitor (janitor)]

This bug was fixed in the package network-manager - 0.9.10.0-4ubuntu19

---------------
network-manager (0.9.10.0-4ubuntu19) wily; urgency=medium

  [ Tony Espy ]
  * debian/patches/add_ofono_settings_support.patch: remove code
    that added APN, USERNAME and PASSWORD to NM_SETTING_GSM object.
    NM doesn't actually need access to these settings, and USERNAME/
    PASSWORD can cause issues with NM's secrets needed logic.
  * debian/patches/0001-wwan-add-support-for-using-oFono-as-a-modem-manager.patch,
    debian/patches/lp1461593-add-nm-settings-connection-reset-retries-methods.patch,
    debian/patches/add_ofono_settings_support.patch,
    debian/patches/lp1461593-add-modem-reconnect-delay-to-policy.patch: More changes
    to NMModemOfono's modem_state handling. Added get/set_reset_retries_timeout
    methods to NMSettingsConnection, and use the set method to lower the timeout for
    ofono connections to 30s. Finally added a 5s delay to NM_POLICY's activation
    logic triggered when a modem device is disconnected. This allows modem time to
    settle and NM to process the resulting DBus state changes. (LP: #1461593)
  * debian/patches/0001-wwan-add-support-for-using-oFono-as-a-modem-manager.patch,
    debian/patches/lp1445080-modify-device-modem-avail.patch,
    debian/patches/lp1445080-nm-modem-check-for-set-mm-enabled-func.patch,
    debian/patches/lp1461593-add-modem-reconnect-delay-to-policy.patch: These
    changes collectively fix flight-mode on arale ( and other devices ), due to
    some fundemental race conditions in the ofono logic. (LP: #1445080, #1440917)
  * debian/patches/0001-wwan-add-support-for-using-oFono-as-a-modem-manager.patch,
    debian/patches/add_ofono_settings_support.patch: Add support for the ofono
    gprs-context 'Preferred' property. (LP: #1361864)

  [ Mathieu Trudel-Lapierre ]
  * d/p/0002-wifi-cull-the-scan-list-before-signalling-ScanDone-b.patch:
    Re-add schedule_scan() call after we get the ScanDone signal from the
    supplicant. Otherwise we'd do one scan on startup and never scan again.
    (LP: #1445134)

 -- Mathieu Trudel-Lapierre <email address hidden> Wed, 05 Aug 2015 12:17:28 -0400