A brief explanation is necessary...

By default, ofono sets the 'Powered' property of a modem's
ConnectionManager interface to True, this in turn causes the ofono core
to trigger GPRS attachment, which if successful, sets the 'Attached'
property to True.

NetworkManager will only attempt to activate a connection of both
'Attached' and 'Powered' are set to True.

The MTK plugin and modem code currently have logic which prevents both
modems from becoming 'Attached', however this logic is non-deterministic
as timing may effect which modem is set attached first.

If an end-user goes and explicitly changes the SIM selection for mobile
data, ofono will update the gprs settings for both SIMs, such that the
newly selected SIM will be powered, and the other SIM not powered.
>From this point on, this bug will be prevented from happening.

A fix has been proposed in the following branch:

https://github.com/rilmodem/ofono/pull/157

It ensures that only one Modem's ConnectionManager can be powered at any
time.   When it detects a change from False to True of a modem's CM
'Powered' property, either from a call to DBus, or via a loaded gprs
settings file, it causes the other modem's CM 'Powered' property to be
toggled to False.  In essence, similar logic of Cellular Settings.

** Changed in: ofono (Ubuntu)
       Status: Confirmed => In Progress

** Changed in: ofono (Ubuntu RTM)
       Status: Confirmed => In Progress

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1413672

Title:
  The SIM used for data in MTK-based dual-standby modems can change
  after carrier re-registration or reboot

To manage notifications about this bug go to:
https://bugs.launchpad.net/canonical-devices-system-image/+bug/1413672/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to