Libertas firmware on F9 for the XS

[Martin Langhoff]

On Sat, Sep 13, 2008 at 2:11 PM, Ricardo Carrano <carrano at laptop.org> wrote:
> What's more straight than saying: The team recommends that the only
> firmware to be used with the new 2.6.25 kernel is 22.p18

As a developer, I can relate 100% to that. As a release manager (and I
have to play both here) what I want to know is how much of a "well
understood stable release" this is. There is a range that spans from
"this is a dev snapshot, compiles and has my latest code so use it!"
at one end, and "field tested to the bitter end" at the other.

>From what I see, a wireless firmware/driver combo seems to be a tricky
bit of software in that -- due to a huge number of variables in
interoperability -- it can never be 100% right. I don't expect to hear
it's perfect (though I'll be deeply impressed if it is).

Instead, what I was hoping for is some understanding of how many
things have been tested, and what problems have been found. Not that
they'd be "your fault" as in "you implemented the standard wrong"  --
I'm sure 80% of the wireless devices out there have "quirks".
Interoperability is tricky.

> There may be others, but they are not "known bugs" so far.

Now, knowing what I know about network interop, if no problems have
been found... can you give me a rough idea of what devices and modes
this driver/firmware pair has been tested with?

> By the way. Actually, no. Even the WPA issue should not interfere with
> the XS.

I agree. The WPA issue is not one that bothers the XS. I just want the
list of issues to check whether any affects it. You tell me there
isn't such list, and I can believe you, but then... where's the
testing?

> And, I would like to understand what is the connectivity model
> that you are trying to implement on the XS. Are we insisting on using
> active antennae as mesh gateways on the XS? Is it clear to you that we
> do not recommend this at all?

I don't plan to emphasize Libertas devices as mesh gateways - I know
well that they are not recommended. Not closing the door completely on
them  (may become recommended or viable later in the game?).

However, I still work on this for 2 reasons:

 - We'll be trying to get the XS build running on the XO hardware.
This should be doable reasonably soon, and will be a boon for very
small schools.

 - Again for small schools, the Libertas device can be cheaper than an
AP so it could still be an option

Both are a good case for thinmac too.

> Simply put. The model of having a bunch of school servers with a bunch
> of active antennas to support hundreds of laptops in 3 mesh clouds
> should be completely abandoned.

We are on the same page on this and changes on the networking settings
in the XS are already planned to better support large schools with
APs.

> I don't recall
> reading any questions on what version should be used with the school
> server, before now. Have this question been asked?

I don't know much about earlier days. But what I am asking is not only
which one do you recommend, but what data have you got to support
that? Seeing just a little bit of formal testing, analysis and
bugtracking would be just the ticket for me.

It's a nasty question - I know - but it's the kind of questions that
release managers are prone to ask. However, I need the information.

cheers,



m
--
 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff - working code first
 - http://wiki.laptop.org/go/User:Martinlanghoff