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Message-ID: <f69f27acb8171cea5fdf6ceedb92efbced909300.camel@sipsolutions.net>
Subject: Re: [PATCH] wifi: rtlwifi: Fix setting the basic rates
From: Johannes Berg <johannes@sipsolutions.net>
To: Ping-Ke Shih <pkshih@realtek.com>, Bitterblue Smith
	 <rtl8821cerfe2@gmail.com>, "linux-wireless@vger.kernel.org"
	 <linux-wireless@vger.kernel.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Date: Mon, 19 Feb 2024 11:04:00 +0100
In-Reply-To: <afded3d1768247cca613f55943a013aa@realtek.com>
References: <35165caf-337c-4da0-b55c-c1a7081a1456@gmail.com>
	 <afded3d1768247cca613f55943a013aa@realtek.com>
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On Mon, 2024-02-19 at 07:37 +0000, Ping-Ke Shih wrote:
> >=20
> > I'm not sure if this is enough. Should we also handle
> > BSS_CHANGED_BASIC_RATES? But bss_conf->basic_rates is only 0xf (CCK
> > rates only) and the out-of-tree Realtek drivers want to use the 6, 12,
> > and 24M rates as well. If ieee80211_find_sta() returns NULL, how can we
> > know if OFDM rates are supported?

This whole find_sta is a bit questionable - basic rates are from the BSS
configuration anyway?

> > I'm also not sure if it's okay to set the basic rates later than
> > originally intended, but it's still better than never.
>=20
> bss_conf->basic_rates is from AP beacon basically, and only the supported=
 rates
> with 0x80 bit are basic rates, which is minimum rates requirement to the =
AP.
> Thus, I think it is not suitable to consider basic rates as RTS rate.=20
>=20

But you have to consider them? Control response rates are very precisely
defined in the spec, see 10.6.6.5.2 "Selection of a rate or MCS".

I also have a bunch of explanations about that in the iwlmvm driver in
drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c around line 360.

johannes