> Date: Mon, 22 Apr 2019 12:12:18 +0200
> From: Stefan Sperling <[email protected]>
> 
> This should make scans on iwn(4) more reliable.
> 
> At present the calculation of 'passive' in iwn_get_passive_dwell_time()
> serves no purpose because iwn_limit_dwell() ignores its second parameter.
> This looks like an accident.
> 
> Effectively, this diff extends channel dwell time during passive scans
> by 20ms on 2Ghz and by 10ms on 5GHz, on top of the default dwell time
> of 100ms. Given that most APs use a beacon interval of 100ms, these
> small extensions could make the difference between catching a beacon
> and not catching it.
> 
> In if_iwnreg.h there's even a comment which says:
>  * For the most reliable scan, set > AP beacon interval (typically 100msec).
> 
> ok?

ok kettenis@

> diff 1afff35ce04b6804bc4ca370e3ec3962d8a5f38a /usr/src
> blob - c7bc1ddd8dc8f2637094971d01a3c2915c4ab628
> file + sys/dev/pci/if_iwn.c
> --- sys/dev/pci/if_iwn.c
> +++ sys/dev/pci/if_iwn.c
> @@ -4703,7 +4703,7 @@ iwn_limit_dwell(struct iwn_softc *sc, uint16_t dwell_t
>               return (MIN(IWN_PASSIVE_DWELL_BASE, ((bintval * 85) / 100)));
>  
>       /* No association context? Default */
> -     return (IWN_PASSIVE_DWELL_BASE);
> +     return dwell_time;
>  }
>  
>  uint16_t
> 
> 

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