From: James Cameron <quozl@laptop.org>
To: Jean Pierre TOSONI <jp.tosoni@acksys.fr>
Cc: Kalle Valo <kvalo@codeaurora.org>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"ath9k-devel@qca.qualcomm.com" <ath9k-devel@qca.qualcomm.com>
Subject: Re: [PATCH v2] ath9k: mark RSSI as invalid if frame received during channel setup
Date: Thu, 15 Feb 2018 08:30:26 +1100 [thread overview]
Message-ID: <20180214213025.GB17837@us.netrek.org> (raw)
In-Reply-To: <AM4PR0101MB230538DEEFCFFC0E0F4437A2E4F50@AM4PR0101MB2305.eurprd01.prod.exchangelabs.com>
On Wed, Feb 14, 2018 at 04:26:42PM +0000, Jean Pierre TOSONI wrote:
> ath9k returns a wrong RSSI value for frames received in a 30ms time
> window after a channel change. The correct value is typically 10dB
> below the returned value.
How was your correct value determined?
> This was found with a Atheros AR9300 Rev:3 chip (WLE350NX / JWX6083
> cards), during offchannel scans.
>
> Mark the signal value as invalid in this case.
Why not adjust by 10dB?
Speculating: in a typical card, RSSI is calculated by firmware from
readings of ADCs attached to the receiver. Firmware may average
several readings. Firmware may apply other offsets or calibrations,
based on frequency and temperature. This sounds like a firmware
problem.
> Signed-off-by: Jean Pierre TOSONI <jp.tosoni@acksys.fr>
> [...]
--
James Cameron
http://quozl.netrek.org/
next prev parent reply other threads:[~2018-02-14 21:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-14 16:26 [PATCH v2] ath9k: mark RSSI as invalid if frame received during channel setup Jean Pierre TOSONI
2018-02-14 18:16 ` Steve deRosier
2018-02-15 8:48 ` Jean Pierre TOSONI
2018-02-14 21:30 ` James Cameron [this message]
2018-02-15 5:51 ` Kalle Valo
2018-02-15 7:21 ` James Cameron
2018-02-15 8:52 ` Jean Pierre TOSONI
2018-02-15 11:57 ` James Cameron
2018-02-15 14:45 ` Felix Fietkau
2018-02-15 16:29 ` Jean Pierre TOSONI
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