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Date: Wed, 10 Apr 2024 07:37:37 -0700
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Subject: Re: [PATCH 01/13] wifi: cfg80211: Add provision to advertise multiple
 radio in one wiphy
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To: Johannes Berg <johannes@sipsolutions.net>,
 Vasanthakumar Thiagarajan <quic_vthiagar@quicinc.com>,
 Karthikeyan Periyasamy <quic_periyasa@quicinc.com>,
 ath12k@lists.infradead.org
Cc: linux-wireless@vger.kernel.org
References: <20240328072916.1164195-1-quic_periyasa@quicinc.com>
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 <31f30c0e318904f3a082c7f213576ceb1f407141.camel@sipsolutions.net>
From: Ben Greear <greearb@candelatech.com>
Organization: Candela Technologies
In-Reply-To: <31f30c0e318904f3a082c7f213576ceb1f407141.camel@sipsolutions.net>
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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