[OLPC Networking] Testing the Wireless driver changes

[Michail Bletsas]

There is quite a bit of important history removed from this discussion.

We designed the laptop to be able to do mesh forwarding *all the time*.
This was a fundamental decision because it affected every other choice 
that we made in the wireless subsystem.

One of the issues that it introduced is that it makes the radio deviate 
from what "proper" radio behavior is supposed to be under Linux these 
days: when you bring an interface down (ifconfig eth0 down), its radio 
should be disabled. If you don't bring the interface up on boot, the radio 
should stay off. Pretty clean and simple.

When it comes to our radio - we *designed it* to start forward frames soon 
after you initialize it and keep doing it regardless of what the host 
interface does.
That's why we used a radio with its own CPU and memory. 

So things like "iwconfig eth0 txpower off" might be doing the right thing, 
however they do so (if they do**) indirectly, by controlling the host 
interface.

There is an "iwpriv eth0 radiooff/radioon" IOCTL hook in the firmware 
which was meant to control the radio power directly - it was removed a few 
months ago since it wasn't considered to its thing in the "proper" linux 
manner.

And ever since we keep having this "airplane mode" discussion.....

M.

** I don't know how "iwconfig eth0 txpower off" is implemented, if it uses 
the same IOCTL with "iwpriv eth0 radiooff", then it is doing the right 
thing.



"Edward Cherlin" <echerlin at gmail.com> wrote on 01/16/2008 06:56:17 PM:

> On Jan 16, 2008 2:46 PM, Dan Williams <dcbw at redhat.com> wrote:
> On Wed, 2008-01-16 at 20:22 -0200, Ricardo Carrano wrote:
> > I believe what you want is "radio off", not "mesh stop".

> "radio off" == iwconfig eth0 txpower off 
> 
> that's always been around from day #1.
> 
> That turns off the radio for this session. How do you disable it so 
> it doesn't come on at the next boot? 
> 
> -- 
> Edward Cherlin 
> End Poverty at a Profit by teaching children business
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