[RFC] [PATCH] wifi: ath12k: wait for chan update in reg_notifier

[Kang Yang]

On 12/10/2024 6:00 AM, Ionic wrote:
> * On 12/9/24 22:47, Mihai Moldovan wrote:
>> Currently, setting a new regdomain is asynchronous in ath12k, in the
>> [...]
> 
> Making the reg_notifier synchronous with the actual reg update fixes the 
> issue.
> 
> In short, when setting a new reg domain, the reg notifier is called as 
> the last step by cfg80211 before sending a regdom change event over 
> netlink, but since the reg_notifier is not waiting for the hardware to 
> apply the new country code to the firmware and update things like the 
> channel list, things can fail in user space.
> 
> 
> I implemented a regd_update completion in ah and added a wait call in 
> reg_notifier, as well as completing it in regd_update, with 
> (re-)initializers in mac_hw_register and mac_hw_unregister.
> 
> I'm not quite sure if ah is the correct place for that, but it felt like 
> the most appropriate. 

I think this place is right.


> ar is too low-level (since multiple ar can share 
> an ah IIRC) and it should generally not be possible to set per-ar 
> regdomains, although per-phy regdomains are possible, but every phy 
> should have an ah (I guess?). 


If the "phy" you mentioned is one wifi chip, i think you are right.

> Not sure how vdevs play into this.

Each chip at least have one vdev.

> 
> 
> Can you please test and review this? If it's already good, feel free to 
> include it in your series.

I will review and test your "RFC v2"


> 
> 
> ath11k is suffering from the same issue - I just haven't noticed it 
> before because the default regdomain of the ath11k-based card I use is 
> set to US, which allows operations on channel 96 to 144. If I set CN 
> first, I can easily reproduce the same issue with ath11k, so I'll have 
> to backport a good patch to ath11k as well.
> 
> 
> 
> Mihai