Re: problem on ACS

[Christian Lamparter <chunkeey@googlemail.com>]

On Friday 29 July 2011 22:50:54 Luis R. Rodriguez wrote:
> On Fri, Jul 29, 2011 at 12:39 AM, MingAnn Ng <devil_eddie01@hotmail.com> wrote:
> > Survey 2 from wlan0:
> >  noise:    -84 dBm
> >  channel active time:  12 ms
> >  channel busy time:  0 ms
> >  channel receive time:  0 ms
> >  channel transmit time:  0 ms
> >  interference factor:  9223372036854775815.000000
> 
> This is caused by log2(0), this if fixed as follows:

> diff --git a/src/ap/acs.c b/src/ap/acs.c
> index aa5498e..04b1e31 100644
> --- a/src/ap/acs.c
> +++ b/src/ap/acs.c
> @@ -125,7 +125,7 @@ static u64 min(u64 a, u64 b)
>   */
>  static u64 log2_sane(u64 val)
>  {
> -	return log2(min(1073741824, val));
> +	return return (!val) ? 0 : log2(min(1073741824, val));
>  }
> 
> 
> I'll send a new version of the last patch with this fix, thanks for
> reporting this.
Wait a sec... I guess you misunderstood my post about the cut-off.
I meant that you can cut of at the bottom by using log2(max(1, val)).
This ensures that the log2 will always be >= 0 anyway. In fact log2(1) = 0.

Regards,
	Chr