Disabling the "Radio" in Sugar disables ability to use any networking adapter

[greenfeld]

Disabling the "Radio" in Sugar's Control panel not only disables an XO's internal 802.11 radio, but currently also disables a user's ability to use any other networking adapter automatically in Sugar.

I'm told this was done to workaround some other networking issues for the 10.1.3 release, and that Sugar/GNOME/NetworkManager's ability to coordinate with each other is not the best.

Users should either leave the "Radio" on, or if power is a concern, other adapters (such as USB ethernet devices, etc.) can be manually configured.

Seen in 10.1.3 os359. To be documented for 10.1.3, fixed in a future release.

[martin.langhoff]

Options:

• We narrow down the functionality to only switch off radio (related: #10575) -- when switching on, it should also ensure networking is on.
• Rework the control panel to manage radio and network, separately

[mikus]

There are two considerations to be balanced: (1) Most of the OLPC users will be computer-illiterate pupils. The fewer controls they need to manage, the more friendly their OLPC experience; (2) Some of the OLPC environments (e.g., 500 pupils in one building) may need special setup. For the technicians involved, the more controls they have available, the more friendly their OLPC experience.

If consideration (1) is more important, then the described behavior of "Radio Off" is not a defect.

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The usual set of communication interfaces that an OLPC might use is:

(A) "Radio" (wireless) connected to an Access Point
(B) "Radio" (wireless) connected to an Ad-Hoc network
(C) "Mesh" (wireless) [implemented as in 2008]
(D) Wired network (through external adapter)
(E) Wireless network (through external adapter)

To prevent use of (A) (after disconnecting): Click on 'My Settings' -> 'Network' -> "Discard Network History". If the "Discard Network" capability gets properly implemented, interface (A) will not be used again unless an Access Point icon gets clicked in Neighborhood View, [I don't have a school server to test with -- "Register" as well might be setting up a persistent connection.]

To prevent use of (B) (after disconnecting): Gconf setting /desktop/sugar/network/adhoc needs to be set false. [Not something expected to be known by computer-illiterate users.]

To prevent use of (C) (after disconnecting): Zero needs to be emitted to /sys/class/net/eth0/lbs_mesh. [Not something expected to be known by computer-illiterate users.]

To prevent use of (D) or (E) (after disconnecting): Unplug the external adapter.

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It is possible that in some builds there may exist additional "caches" (to remember interface states) which the above-listed procedures do not reset. Also, there may be interactions between the states of the individual interfaces. [For instance, I would expect a proper implementation of "Radio Off" to disable all internal wireless interfaces (A and B and C),]