Re: [RFC v2 5/6] mac80211_hwsim: add TPC per packet support

From: Jonas Jelonek <jelonek.jonas@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org, Felix Fietkau <nbd@nbd.name>
Subject: Re: [RFC v2 5/6] mac80211_hwsim: add TPC per packet support
Date: Thu, 26 Jan 2023 17:52:21 +0100	[thread overview]
Message-ID: <E26F68F9-337D-4163-AA0F-A43E50864AEB@gmail.com> (raw)
In-Reply-To: <3e269bce8d73577fb1183697655d6ad66edf866f.camel@sipsolutions.net>

> On 19. Jan 2023, at 16:09, Johannes Berg <johannes@sipsolutions.net> wrote:
> 
> On Thu, 2023-01-19 at 15:32 +0100, Jonas Jelonek wrote:
>>> 
>>> Not sure I like this either - I think we should probably create the
>>> wiphys dynamically for most features these days?
>> 
>> just to make sure I got it correctly: so you propose that these
>> params, that are 
>> currently done with module_param(), should be switched to a dynamic
>> netlink approach, or only for TPC and RCTBL for now?
> 
> We do have dynamic parameters for all the module parameters I believe,
> but we've shied away from actually removing the existing module
> parameters for legacy/compatibility reasons.
> 
> However, I think that for new parameters, there's really no good reason
> to provide module parameters, since the test scripting etc. can
> dynamically create wiphys with the necessary capabilities. Even the
> hostap/hwsim tests can and do already do that :)

From what I’ve seen there is no dynamic parameter for RCTBL yet but I can combine
this with my additional TPC parameter. Then this can be set via netlink.

>> As a first step I focused on providing a proof-of-concept
>> implementation in hwsim for my
>> TPC proposal, implementing netlink to set tx power and other could be
>> part of the next step.
>> Do you think this could be fine or do you propose something different?
> 
> I'm not quite sure what you mean by that, tbh. I guess I kind of thought
> you were going to adjust minstrel to do TPC automatically.
> 
> We already have netlink support for setting per-station TX power which I
> guess this should then listen to? See NL80211_ATTR_STA_TX_POWER_SETTING
> and NL80211_ATTR_STA_TX_POWER etc. I think it's not supported in
> mac80211, but probably could easily be after your patches?

I guess that can be part of some follow-up patches after these patches here are upstream.
I would agree that this should somehow listen to the mentioned attributes then.

We want to do joint RC and TPC in minstrel, and to allow fine-grained TPC as it is already
possible with RC. Minstrel will also be adjusted in one of the next steps.
This RFC basically should “prepare” mac80211 to be used for fine-grained TPC. I think,
driver support and Minstrel support should be the next steps after the structures are fixed.
But I include hwsim here to have at least a test-case. Hope you get what I mean :)

Jonas