Re: Force use of 5GHz band

[James Prestwood <prestwoj@gmail.com>]

On 9/16/23 8:18 AM, Denis Kenzior wrote:
> Hi James,
> 
>>
>> How would you prefer I do this? We've got quite a few modules using 
>> scan APIs so I question if we want to filter the frequencies before 
>> calling scan_*
> 
> We should be doing that already, no?  Any code that specifies scan 
> frequencies in some way should be aware of wiphy band capability and 
> regdom.
> 
>>
>> If we filter in scan.c and call back as if the scan returned no 
>> results we shouldn't need to touch anything except scan.c. The 
>> downside is its a bit of 
> 
> I really rather not generate dummy/bogus callbacks.  That just pollutes 
> debug logs and makes the code hard to follow.  Station would be most 
> affected here since it breaks up the 2.4Ghz band scan quite a bit.
> 
> If 2.4 is turned off, it should just skip those requests entirely.
> 
>> wasted work doing this since we have to create requests and work items 
>> for nothing, but the alternative of adding this specific logic to each 
>> module using scan calls seems worse IMO, what do you think?
>>
> 
> One thing to keep in mind is that some devices operate only on 2.4G.  
> For example WSC/WPS might only perform push button operations on 2.4 GHz 
> band and not 5G.  Might be similar with DPP?  So for compatibility 
> reasons maybe this should be a station-only feature?

Yeah, keeping it station only is good with me. Only part that gets nasty 
are periodic scans. Since we scan the entire spectrum and specifying a 
frequency list will break the 6GHz logic we have... So for this I'll 
need to add support to split the scan request if explicit frequencies 
are provided, since periodic scans will need to include a (potentially) 
paired down list if the user disables them.

This could end up being useful though if e.g. a quick scan includes a 
6GHz channel and is able to scan it rather than falling back to a full scan.

> 
> Regards,
> -Denis
>