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Re: NetworkManager-0.7 can't make new wireless connection



On Mon, 2007-10-01 at 14:56 -0400, Matthew Miller wrote:
> On Mon, Oct 01, 2007 at 02:25:09PM -0400, Dan Williams wrote:
> > > > A driver based on mac80211 perhaps?  which one?  At least ipw2200 has
> > > > been pretty stable for me; I have also tried rt76_usb + mac80211 and
> > > > that's been OK.
> > > orinoco_pci....
> > I've got an orinoco pcmcia part, will test with that.
> 
> Cool, thanks.

So I tried this.  It sucks.  The orinoco driver has problems scanning
when wpa_supplicant is active, which it really shouldn't care about.
Plus, I only get 2 or 3 results from the driver anyway, when my internal
ipw2200 card gets 10.  Maybe the internal Thinkpad antenna is just that
much better.  I _was_ able to connect with the orinoco card and keep the
connection, but gradually all scan results dropped out of the list, and
even 'iwlist eth2 scan' would only return the AP I was connected to,
even though there are other strong APs nearby.

I think there's a lot of room for improvement in the driver.  It's
pretty racy with scan results.  First, reading of scan results should be
decoupled from the actual process of scanning, and scan results should
be aged before being dropped completely.  There's a fairly large window
of time where scan results won't be available to the caller even though
a successful scan could have happened a second ago.  The scan_inprogress
flag shouldn't have any semantics leak out to userspace.

I did a patch for airo a year or two ago that cleaned exactly this sort
of behavior up.  Not sure that really helps you much.  As a quick test,
what happens if you do a few back-to-back 'iwlist ethX scan' commands?

Dan



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