Re: [PATCH v2] Revert "cfg80211: fix processing world regdomain when non modular"

[Johannes Berg <johannes@sipsolutions.net>]

On Fri, 2019-06-14 at 13:16 +0000, Hodaszi, Robert wrote:
> This reverts commit 96cce12ff6e0bc9d9fcb2235e08b7fc150f96fd2.
> 
> Re-triggering a reg_process_hint with the last request on all events,
> can make the regulatory domain fail in case of multiple WiFi modules. On
> slower boards (espacially with mdev), enumeration of the WiFi modules
> can end up in an intersected regulatory domain, and user cannot set it
> with 'iw reg set' anymore.
> 
> This is happening, because:
> - 1st module enumerates, queues up a regulatory request
> - request gets processed by __reg_process_hint_driver():
>   - checks if previous was set by CORE -> yes
>     - checks if regulator domain changed -> yes, from '00' to e.g. 'US'
>       -> sends request to the 'crda'
> - 2nd module enumerates, queues up a regulator request (which triggers
> the reg_todo() work)
> - reg_todo() -> reg_process_pending_hints() sees, that the last request
> is not processed yet, so it tries to process it again.
> __reg_process_hint driver() will run again, and:
>   - checks if the last request's initiator was the core -> no, it was
> the driver (1st WiFi module)
>   - checks, if the previous initiator was the driver -> yes
>     - checks if the regulator domain changed -> yes, it was '00' (set by
> core, and crda call did not return yet), and should be changed to 'US'
> 
> ------> __reg_process_hint_driver calls an intersect
> 
> Besides, the reg_process_hint call with the last request is meaningless
> since the crda call has a timeout work. If that timeout expires, the
> first module's request will lost.

It's pointless to resend when I still have the original patch pending,
at least without any changes.

That said, I looked at this today and I'm not sure how the code doesn't
now have the original issue again?

johannes