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Date: Wed, 22 May 2024 16:55:16 +0200
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Subject: Re: [PATCH 00/13] wifi: Add multi physical hardware iface combination
 support
To: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>,
 ath12k@lists.infradead.org, johannes@sipsolutions.net
Cc: linux-wireless@vger.kernel.org
References: <20240328072916.1164195-1-quic_periyasa@quicinc.com>
From: Felix Fietkau <nbd@nbd.name>
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On 28.03.24 08:29, Karthikeyan Periyasamy wrote:
> The prerequisite for MLO support in cfg80211/mac80211 is that all the links
> participating in MLO must be from the same wiphy/ieee80211_hw. To meet this
> expectation, some drivers may need to group multiple discrete hardware each
> acting as a link in MLO under single wiphy. So it required to have some
> sort of mapping while describing interface combination capabilities for
> each of the underlying physical hardware. This patch set tries to add an
> infrastructure to advertise underlying hw specific capabilities like
> channel and interface combinations.
> 
> Some of the todos
> 
>   - More than one concurrent monitor mode support each operating on
>     different channels under one ieee80211_hw
>   - Mechanism for each underlying radio specific configurations like
>     txpower, channel, etc.
> 
> RFC series Link: https://lore.kernel.org/linux-wireless/20220920100518.19705-1-quic_vthiagar@quicinc.com/

FYI, I made a replacement for the wiphy radio hardware reporting parts 
of this series with a different design:
https://patchwork.kernel.org/project/linux-wireless/list/?series=855042

The key differences are:
- Only band bitmask and optionally frequency ranges are provided, so no 
per-radio channel list
This is easier to track and vastly reduces the amount of data sent to 
user space in the wiphy dump

- No integration with ifcomb. I don't really see the need for that one 
at this point. It can easily be added later if it's actually needed.

- Validation happens in mac80211 instead of cfg80211, because that 
removes a lot of complexity
The radio id is tracked per chanctx and only one chanctx per radio is 
allowed.
I think if we ever get a non-mac80211 driver that needs multi-radio 
support, it should just do its own validation, since that's likely going 
to be less complex than having cfg80211 do it in the first place.

- Felix