Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx> 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@xxxxxxxxx> > Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx> > Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx> 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@xxxxxxxxxx/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches