Re: [PATCH 01/13] wifi: cfg80211: Add provision to advertise multiple radio in one wiphy

Ben Greear
2024-04-10T14:37:48Z

On 4/10/24 00:56, Johannes Berg wrote:
> On Fri, 2024-03-29 at 07:47 -0700, Ben Greear wrote:
>> On 3/29/24 07:30, Johannes Berg wrote:
>>> On Fri, 2024-03-29 at 19:41 +0530, Vasanthakumar Thiagarajan wrote:
>>>>>
>>>>>> + * @hw_chans: list of the channels supported by every constituent underlying
>>>>>> + * hardware. Drivers abstracting multiple discrete hardware (radio) under
>>>>>> + * one wiphy can advertise the list of channels supported by each physical
>>>>>> + * hardware in this list. Underlying hardware specific channel list can be
>>>>>> + * used while describing interface combination for each of them.
>>>>>
>>>>> I'd expect there to be a limit on channels being within a single band on
>>>>> a single "hardware"?
>>>>>
>>>>
>>>> There are ath12k hardware supporting multiple band which need to be
>>>> registered under one mac80211_hw/wiphy. This design is to support such
>>>> hardware.
>>>
>>> Oh OK, that was something that I didn't have in mind any more, or never
>>> knew or paid attention to.
>>
>> Would it work to leave the phy reporting pretty much as it is now, but add
>> a 'associated_peer_radios' list section, so that each phy could report the phys
>> associated with it? Then user-space, driver, mac80211 etc could look up the
>> other phys as needed to get a full picture?
>>
>
> There's not really a good way to _do_ that short of creating multiple
> wiphys, but that causes _massive_ complexity in the stack (both cfg80211
> and mac80211) so we rejected it years ago.

I thought the problem ath12k is trying to fix is that there are currently multiple phys (radios) that needed to be made to
look like a single phy?

For dual and tri-concurrent radios, I think we will need them to look like 3 individual radios for non-MLO use
cases, but I guess there will be also some way to treat them as a single entity when using MLO.

For instance, mt7996 currently reports 3 single-band wiphys, and each can be used independently.
But assuming it starts supporting MLO, then those 3 single band wiphys will need to start acting
at least somewhat like a single entity (while also concurrently being able to act as individual
wiphys so that one can do a mix of MLO and non MLO sta/AP.)

Maybe I'm missing the entire point of the ath12k patches though...

Thanks,
Ben

>
> johannes
>

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