Re: [PATCH 1/2] nl80211: vendor-cmd: qca: add dynamic SAR power limits

From: Brian Norris <briannorris@chromium.org>
To: Kalle Valo <kvalo@codeaurora.org>
Cc: Johannes Berg <johannes@sipsolutions.net>,
	Jouni Malinen <j@w1.fi>, Pkshih <pkshih@realtek.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	"ath10k@lists.infradead.org" <ath10k@lists.infradead.org>
Subject: Re: [PATCH 1/2] nl80211: vendor-cmd: qca: add dynamic SAR power limits
Date: Thu, 16 Jul 2020 11:56:39 -0700	[thread overview]
Message-ID: <CA+ASDXOAzPuOn_rMsRj4t56kC-TgoG0p5WhSTPJjB8xTTq5kfg@mail.gmail.com> (raw)
In-Reply-To: <87lfjjx0o7.fsf@codeaurora.org>

On Thu, Jul 16, 2020 at 2:35 AM Kalle Valo <kvalo@codeaurora.org> wrote:
> Brian Norris <briannorris@chromium.org> writes:
> > Really, I could live with per-vendor APIs. My primary goal is to get
> > these upstream in some form, so vendors can stop using things like
> > this as a reason for shipping us non-upstream code, and so we can
> > reduce the delta between upstream and Chrome OS kernels.
> >
> > I also think that, for the cases that warrant it (i.e., the option 2
> > -- Realtek and Qualcomm cases, so far), it would be good to have a
> > common API, but that's a somewhat secondary concern for me.
>
> So to me it feels like the best solution forward is to go with the
> vendor API, do you agree? We can, of course, later switch to the common
> API if we manage to create one which is usable for everyone.

That's fine with me. That's pretty much what I said in my first email:

"Anyway, I don't really object with starting out with a
Qualcomm-specific and a Realtek-specific vendor command to implement
nearly the same feature, but I'd prefer if people did engage in some
healthy discussion about why they can't share an API, with the hopes
that maybe they can converge someday."

I think we've had some healthy (though very protracted) discussion,
and I don't think I've seen anyone bring up anything I wasn't already
aware of that would prevent eventual consolidation. As long as we
acknowledge those things (item 2 at
https://wireless.wiki.kernel.org/en/developers/documentation/nl80211#vendor-specific_api),
I'm happy.

> > Also, Kalle had some concerns about stable ABI questions: shouldn't we
> > bake in some kind of "check for support" feature to these kinds of
> > APIs [3]? That would help ease transition, if we do start with a
> > vendor API and move to a common one in the future.
>
> Yeah, that sounds like a good idea but I don't think that should block
> these patches.

OK, well it was your concern first, IIRC :)

So what's next? A v2 that only needs a bit of updated description
about "why a vendor API"? And Realtek can feel free to submit this [1]
shortly?

Thanks,
Brian

[1] Series: rtw88: Add SAR implementation
https://patchwork.kernel.org/project/linux-wireless/list/?series=238219&state=*