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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Linus =?utf-8?Q?L=C3=BCssing?= <ll@simonwunderlich.de>,
        Adrian Chadd <adrian@freebsd.org>,
        Linus =?utf-8?Q?L=C3=BCssing?= <linus.luessing@c0d3.blue>
Cc:     Johannes Berg <johannes.berg@intel.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Kalle Valo <kvalo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>,
        Simon Wunderlich <sw@simonwunderlich.de>,
        Sven Eckelmann <sven@narfation.org>,
        ath10k <ath10k@lists.infradead.org>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mac80211: Fix wrong channel bandwidths reported for
 aggregates
In-Reply-To: <31e87fa2-6fea-5fe2-ab80-6050da9af7ce@simonwunderlich.de>
References: <20220718222804.21708-1-linus.luessing@c0d3.blue>
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 <31e87fa2-6fea-5fe2-ab80-6050da9af7ce@simonwunderlich.de>
Date:   Wed, 20 Jul 2022 12:57:34 +0200
Message-ID: <87cze0kq5d.fsf@toke.dk>
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Linus L=C3=BCssing <ll@simonwunderlich.de> writes:

> On 19/07/2022 17:03, Adrian Chadd wrote:
>> Hi!
>>=20
>> It's not a hardware bug. Dating back to the original AR5416 11n chip,
>> most flags aren't valid for subframes in an aggregate. Only the final
>> frame has valid flags. This was explicitly covered internally way back
>> when.
>
> Ah, thanks for the clarification! I see it in the datasheet for the=20
> QCA9531, too, now. And thanks for the confirmation, that what we are=20
> doing so far is not correct for ath9k.
>
> Words 0+2 are valid for all RX descriptors, 0+2+11 valid for the last RX=
=20
> descriptor of each packet and 0-11 for the last RX descriptor of an=20
> aggregate or last RX descriptor of a stand-alone packet. Or in other=20
> words, word 4, which contains the 20 vs. 40 MHz indicator, is invalid=20
> for any aggregate sub-frame other than the last one. I can rename that=20
> in the commit message.
>
>
> Another approach that also came to my mind was introducing more explicit=
=20
> flags in cfg80211.h's "struct rate_info", like a RATE_INFO_BW_UNKNOWN in=
=20
> "enum rate_info_bw" and/or RATE_INFO_FLAGS_UNKNOWN in "enum=20
> rate_info_flags". And setting those flags in ath9k_cmn_process_rate().
>
> The current approach is smaller though, as it simply uses the already=20
> existing flags. If anyone has any preferences, please let me know.

I have no objections to doing it in mac80211 like you're proposing here :)

-Toke