Re: [RFC 2/3] mac80211: Support scanning only current active channel.

[Ben Greear <greearb@candelatech.com>]

On 01/20/2011 09:39 AM, Johannes Berg wrote:
> On Thu, 2011-01-20 at 09:32 -0800, greearb@candelatech.com wrote:
>
>> -	ieee80211_offchannel_stop_beaconing(local);
>> +	if (local->ops->sw_scan_start_cur&&
>> +	    local->scan_req->n_channels == 1&&
>> +	    local->scan_req->channels[0] == local->hw.conf.channel) {
>> +		__set_bit(SCAN_ON_CUR_CHANNEL,&local->scanning);
>> +		drv_sw_scan_start_cur(local, true);
>> +	} else
>> +		drv_sw_scan_start(local);
>
> This doesn't seem to make much sense either -- even if we do a scan over
> multiple channels we should be able to optimise the part on the current
> channel (maybe put it at the beginning or end too).

Maybe..but user-space can specify the channels it wants to scan,
and I assume that means what order to scan them in.  I have no
idea if changing that order would confuse some application.

It seems to me that it would take quite a bit of re-work of the
mac80211 scanning logic to deal with scanning on the current
channel w/out affecting other tx/rx packets (as my patch attempts
to do), without setting some explicit flag before you enter
the scan state machine.

Thanks,
Ben

>
> johannes


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com