Re: [PATCH wireless-next v2 1/2] wifi: mac80211: Add eMLSR/eMLMR action frame parsing support

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Mon, 2026-01-26 at 23:41 +0100, Lorenzo Bianconi wrote:
> > 
> > > Per spec I'm also not sure what the MCS map should be when it's not
> > > included in the frame?
> > 
> > IIUC the mcs map value are supposed to be in Operation mode notification frame
> > just for eMLMR. I think the driver should check if the bit is set in
> > ieee80211_eml_params control field to verify if mcs_map_bw values are valid.
> 
> Yeah you're right, the MCS Map is always present if EMLMR Mode is set to
> 1. I thought it was also optional and then what values should you use?
> 
> Can't mac80211 validate the values?

I guess we can validate eMLMR Supported MCS and NSS Set subfiled according to
the table 9-417t available in P802.11be standard.

> 
> > Reading the standard, it is not clear to me if mcs map values are supposed to be
> > added in the Notification frame sent by the AP. What do you think?
> 
> Hmm. I thought no, but then the language says it's present when the
> EMLMR Mode is set to 1, so ... it would have to be? Strange, because
> it's not really defined (well) in this direction.
> 
> OK, I guess the memcpy was right after all:
> 
>    An AP affiliated with the AP MLD that receives an EML Operating Mode
>    Notification frame from a non-AP STA affiliated with the non-AP MLD
>    should send an EML Operating Mode Notification frame to confirm the
>    mode switch at the AP MLD to the non-AP STA with EML Control field
>    set to the same value as EML Control field in the received EML
>    Operating Mode Notification frame from the non-AP STA before the
>    transition timeout expires.
> 
> But I think better restrict memcpy() then to just the EML Control field
> and build the action header etc. directly.

I guess we can just memcpy() control field + link_bitmap (if present) +
eMLMR Supported MCS and NSS Set subfiled (if present). Agree?

Regards,
Lorenzo

> 
> johannes

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