[PATCH] Avoid unnecessary triggering of rescans

Helmut Schaa hschaa
Wed Feb 27 10:16:29 PST 2008

Am Mittwoch, 27. Februar 2008 18:29:26 schrieb Dan Williams:
> On Wed, 2008-02-27 at 18:00 +0100, Helmut Schaa wrote:
> > Am Mittwoch, 27. Februar 2008 17:26:15 schrieb Dan Williams:
> > > > > Does the driver include the BSS in scan results? I would hope that
> > > > > at least the BSSID is included even if the network is hidden (if
> > > > > not, the driver should be fixed..).
> > > >
> > > > The currently associated AP is not in the scan results at all :(
> > > > So I guess the driver needs a fix.
> > >
> > > Yeah, your driver sucks and needs fixing :)  If the driver/card can't
> > > handle specific SSID scans through SIOCSIWSCAN and the resulting probe
> > > responses correctly, there's something wrong in the driver that you
> > > need to fix.  Your driver should work correctly with ap_scan=1 and
> > > scan_ssid=1.
> >
> > Scanning for a specific ESSID works just fine. It's only the currently
> > associated AP which is missing.

I was not that exact here, sorry.
In general, scanning for a specific ESSID works fine. But while being 
connected to an hidden AP a "normal" scan (no specific ESSID) does not return 
the currently connected AP.

> Sounds like the driver needs a clue; if the driver isn't even returning
> the currently associated BSS in the scan results that's pretty wrong.
> However, not many drivers currently do this explicitly.
> I'd argue that the supplicant really isn't at fault here; but the driver
> should be doing better.  Are you using scan_ssid=1 and ap_scan=1, or
> ap_scan=2 here?  If you're using ap_scan=1/scan_ssid=1, then there's
> really no excuse for the driver's behavior.  If you're using ap_scan=2,
> and the driver supports SSID scans, try using ap_scan=1/scan_ssid=1.

I specified ap_scan=1 and scan_ssid=1 in my configuration but the scan I was  
triggering with iwlist is not a scan for a specific SSID. The issue does not 
pop up when initiating a scan for the associated SSID with iwlist.


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