[PATCH] don't continually reschedule specific scans

Dan Williams dcbw
Mon Jun 2 12:20:21 PDT 2008

On Mon, 2008-06-02 at 15:01 -0400, Pavel Polischouk wrote:
> Dan Williams wrote:
> > In situations where the driver does background scanning and sends a
> > steady stream of scan results, wpa_supplicant would continually
> > reschedule the scan.  This resulted in specific SSID scans never
> > happening for a hidden AP, and the supplicant never connecting to the AP
> > because it never got found.  Instead, if there's an already scheduled
> > scan, and a request comes in to reschedule it, and there are enabled
> > scan_ssid=1 network blocks, let the scan happen anyway so the hidden
> > SSID has a chance to be found.
> >   
> Tested the patch as a possible way to fix "failure scenario 1" of this 
> bug: https://bugzilla.redhat.com/show_bug.cgi?id=449215
> The situation does improve - it is more often able to break the scanning 
> deadlock, associate and proceed to authentication stage.

You'll need to pair this patch with the ipw2200 patch I just re-posted
for ipw2200 direct scan queuing (attached so you don't have to find it).
The combination makes ipw2200 + wpa_supplicant a lot happier with hidden


> However, it doesn't work every time. Sometimes the scanning still times 
> out. I do see the following lines in the log (generated with single -d):
> ---------------------------------
> No suitable AP found.
> Not rescheduling scan to ensure that specific SSID scans occur
> Starting AP scan (specific SSID)
> ...
> ------------------------------------
> However, subsequent arriving lists of available APs still list my AP as 
> <hidden>. Is it possible the driver somehow ignores the scan request for 
> a specific AP? Or supplicant somehow loses the correct scan lists?  The 
> driver is ipw2200.
> Also, I sometimes see in the log file that wpa_supplicant attempts to 
> associate with AP 00:00:00:00:00:00, thinking it matches my ESSID.
> Pavel
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