Re: periodic_update(): Roamed ...

[Howard Chu <hyc symas com>]

Dan Williams wrote:
> On Mon, 2009-04-20 at 15:37 -0700, Howard Chu wrote:
> > Howard Chu wrote:
> > > This is probably more related to the ath9k driver, but I wanted to start here
> > > in case anyone is familiar with it. I've been seeing this for the past couple
> > > months, and I just now rebuilt NM fresh from git and it's still happening:
> >
> > I seem to have ruled out the driver; doing a kill -9 on NetworkManager so it
> > doesn't have the opportunity to tear down the connection on exit, shows that
> > the wifi connection works perfectly once NetworkManager is gone. No
> > disassociation messages in dmesg, no pauses in ssh sessions, etc.
>
> Don't rule out the driver.  Does the driver always return the currently
> associated AP in the scan list?  If not, you might hit this.  And the
> driver is being stupid, because of *course* the AP you're currently
> connected to should always be in the scan list, unless you're no longer
> connected to it.
>
> The code in NM grabs the SSID&  BSSID on a 6 second timer, and tries to
> find that AP in the scan list.  If it can't find it (because the driver
> didn't return that AP in the scan list) then it reports none.
>
> If that's your problem, it's a driver problem.

How would I check this? Should it be obvious from "iwlist scan" ? That returns 
the current AP along with the other visible ones.

Also, reviewing the comments in bug 291760, this problem is not just isolated 
to the ath9k driver. It's also being reported for ath5k, wl, iwl3945, ipw2100, 
rtl8187, and b43, across multiple kernel and driver revisions. As such it 
seems unlikely to be the drivers' fault.

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/291760

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/