Re: [PATCH 00/13] wifi: Add multi physical hardware iface combination support

Felix Fietkau
2024-05-22T14:55:39Z

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