[PATCH 1/2] nl80211: add support to enable/disable bss color collision detection

[Nicolas Cavallari]

On 19/01/2023 15:02, Johannes Berg wrote:
> On Mon, 2022-12-26 at 14:03 +0530, Rameshkumar Sundaram wrote:
>> As per 802.11ax-2021, STAs shall process BSS Color Change Announcement
>> (BCCA) from AP and switch to new color, but some STAs aren't processing
>> BCCA from AP and not doing color switch, causing them to drop data
>> frames from AP post color change.
>>
>> Provide an option to disable color collision detection and therefore
>> not to do BCCA to mitigate the same from AP. If it's required in case
>> where STA supports BCCA handling, then it can enabled in AP using this
>> option.
>>
> 
> You should probably split this into cfg80211 and mac80211.
> 
> Also, this doesn't really seem to make a lot of _sense_ since nothing in
> the kernel actually acts on detection of a color collision - hostapd is
> acting on that.
> 
> So since you can easily make hostapd ignore the event, why do you even
> need this?

This may not be related, but the software color collision detection 
sends a netlink message for every colliding frame and it can hose up the 
system if the other network is very active.

Also, cfg80211_bss_color_notify() complains that the wdev lock isn't held.