Re: Scan fails to find wireless networks

On Thu, Oct 14, 2004 at 05:32:14AM +0200, Joerg Albert wrote:
> On Tue, 12 Oct 2004, Mike Pinna wrote:
> > [...] complete packet loss for around six seconds after the interface
> > comes up:
> Yes, that's the same here:
>
> [...]
> 
> Most of the time is spent waiting for the result of two scan runs (~ 2.5 s
> each) - you see it if you exec.
> 	iwpriv wlan0 set_debug 0x180003
> before the above line.

OK, well if that's unavoidable I guess it's not that big a deal.

> > at76c503.c: at76c503.c:2905 assertion dev->istate == INIT failed
> 
> I'll look into this during the weekend.

Thanks.

> There was a bug in the i/f to "iwlist wlanX scanning" (I guess you use
> this for scanning) which let it report only a random subset of the whole
> table. It's fixed in the cvs 0.12beta21.

Yes, that's how I do the scan.  I've tried updating to this version but
the behaviour doesn't seem to have improved at all.

> If you still miss some APs, increase the minimum channel time, i.e.
> the device scans on a channel, before it hops to the next one:
> 
> 	iwpriv wlan0 scan_times N 120
> 
> with N = 30,40, ... (N=10 is the default). The 120 is the max. channel
> time, increasing it let iwlist fail here.

This also doesn't seem to make any difference, which is what initially
led me to believe there might be a firmware issue.  Should I notice the
scan taking any longer when I increase the minimum time?  What are the
units these values are measured in?

One thing that seems strange to me (with my lack of understanding of
what's going on here) is that I consistently get a complete list of APs
in the debug logs from the initial scan runs that happen on interface
up.  It seems very odd then that calling `iwlist wlan0 scan' should not
be able to repeat this data.  Are there two different kinds of scan
going on here?  Also, what does it mean when start_scan reports that
channel = 10 ?  I would expect the scan to occur on every channel (and
it seems that it does, picking up APs that aren't on channel 10).

Thanks for your help,
Mike