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Message-ID: <166359136168.17652.16916114902781460375.kvalo@kernel.org>
Date: Mon, 19 Sep 2022 12:42:43 +0000 (UTC)
From: Kalle Valo <kvalo@...nel.org>
To: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
Cc: loic.poulain@...aro.org, davem@...emloft.net, edumazet@...gle.com,
kuba@...nel.org, pabeni@...hat.com, wcn36xx@...ts.infradead.org,
linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
bryan.odonoghue@...aro.org, "Jason A . Donenfeld" <Jason@...c4.com>
Subject: Re: [PATCH v3 1/1] wcn36xx: Add RX frame SNR as a source of system
entropy
Bryan O'Donoghue <bryan.odonoghue@...aro.org> wrote:
> The signal-to-noise-ratio SNR is returned by the wcn36xx firmware for each
> received frame. SNR represents all of the unwanted interference signal
> after filtering out the fundamental frequency and harmonics of the
> frequency.
>
> Noise can come from various electromagnetic sources, from temperature
> affecting the performance hardware components or quantization effects
> converting from analog to digital domains.
>
> The SNR value returned by the WiFi firmware then is a good source of
> entropy.
>
> Other WiFi drivers offer up the noise component of the FFT as an entropy
> source for the random pool e.g.
>
> commit 2aa56cca3571 ("ath9k: Mix the received FFT bins to the random pool")
>
> I attended Jason's talk on sources of randomness at Plumbers and it
> occurred to me that SNR is a reasonable candidate to add.
>
> Cc: Jason A. Donenfeld <Jason@...c4.com>
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
> Signed-off-by: Kalle Valo <quic_kvalo@...cinc.com>
Patch applied to ath-next branch of ath.git, thanks.
e1a6b5d3a971 wifi: wcn36xx: Add RX frame SNR as a source of system entropy
--
https://patchwork.kernel.org/project/linux-wireless/patch/20220915004117.1562703-2-bryan.odonoghue@linaro.org/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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