Re: [PATCH v5] cfg80211: save power spectral density(psd) of regulatory rule

From: Wen Gong <wgong@codeaurora.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Venkateswara Naralasetty <vnaralas@codeaurora.org>,
	ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	wgong=codeaurora.org@codeaurora.org
Subject: Re: [PATCH v5] cfg80211: save power spectral density(psd) of regulatory rule
Date: Mon, 11 Oct 2021 12:06:10 +0800	[thread overview]
Message-ID: <562080d7fc3b7568811c47a8e8e79156@codeaurora.org> (raw)
In-Reply-To: <1222384c2bc7d80bf572b65ab17660477bb27300.camel@sipsolutions.net>

On 2021-09-30 20:50, Johannes Berg wrote:
> On Thu, 2021-09-30 at 10:53 +0800, Wen Gong wrote:
>> > >
>> > > 		chan->max_reg_power =
>> > > 			min_t(int, MBM_TO_DBM(power_rule1->max_eirp),
>> > > 			      MBM_TO_DBM(power_rule2->max_eirp));
>> > >
>> > > For AP + STA concurrency, it should to maintain 2 group of reg rules,
>> > > one is for AP, another is for STA.
>> >
>> > Can we maintain two power rules in the same channel one for AP and one
>> > for STA. In this way, we can update the power rules in the same
>> > channel for both AP and STA from the reg rules.
>> >
>> > Otherwise, we need to maintain multiple channel lists in sband for all
>> > supported power mode combinations to apply the respective power rules
>> > and build channel flags from the multiple reg rules.
>> > right?
>> 
>> If AP+STA is up in the same wiphy/ieee80211_hw, and AP's reg rules is
>> different
>> with STA, then it should maintain muti channel list for each band of 
>> the
>> wiphy/ieee80211_hw by my understand.
> 
> I don't think that's how it works. You can today have AP/STA 
> concurrency
> on a single wiphy with different netdevs, even with mesh or whatever.
> 
>> Currently there is only one "struct ieee80211_supported_band
>> *bands[NUM_NL80211_BANDS]"
>> in "struct wiphy".
>> 
>> I advise to discuss the AP + STA concurrency in another mail thread
>> since it is not relative with this patch.
> 
> I actually explicitly pointed to this thread, but I'm not sure it's so
> clear cut?
> 
> If we have completely separate rules here for AP and STA, we probably
> should have different "max_reg_power" values for AP and STA? Maybe mesh
> is treated like AP, maybe not?
> 
> But I don't know - does PSD really differ between AP and STA?
> 
> Maybe this discussion belongs rather to the power type patch? But that
> didn't add any state!
> 
> 
> So - does this PSD depend on mode? It kind of seems like it shouldn't
> and then this *isn't* the right place to be discussing this, but if PSD
> does in fact depend on the mode then we should be discussing it here?
> 
> Venkatesh seemed to be worried more about LPI/client power etc. as in
> commit 405fca8a9461 ("ieee80211: add power type definition for 6 GHz"),
> but that doesn't add state?
> 
> So what gives? From a regulatory POV it seems PSD should be 
> independent,
> but some other things might be dependent on mode?
> 

As I know, below values maybe all different for the AP and
STATION in the same wiphy/ieee80211_hw, not only PSD.

struct ieee80211_reg_rule {
	struct ieee80211_freq_range freq_range;
	struct ieee80211_power_rule power_rule;
	struct ieee80211_wmm_rule wmm_rule;
	u32 flags;
	u32 dfs_cac_ms;
	bool has_wmm;
	s8 psd;
};

@Venkateswara, please feel free to give more info to Johannes:)

> johannes

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