From: Kalle Valo <kvalo@codeaurora.org>
To: James Cameron <quozl@laptop.org>
Cc: Jean Pierre TOSONI <jp.tosoni@acksys.fr>,
"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 07:51:28 +0200 [thread overview]
Message-ID: <87mv0a6brz.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <20180214213025.GB17837@us.netrek.org> (James Cameron's message of "Thu, 15 Feb 2018 08:30:26 +1100")
James Cameron <quozl@laptop.org> writes:
> 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.
ath9k does not have firmware, only ath9k_htc has it.
--
Kalle Valo
next prev parent reply other threads:[~2018-02-15 5:51 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
2018-02-15 5:51 ` Kalle Valo [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87mv0a6brz.fsf@kamboji.qca.qualcomm.com \
--to=kvalo@codeaurora.org \
--cc=ath9k-devel@qca.qualcomm.com \
--cc=jp.tosoni@acksys.fr \
--cc=linux-wireless@vger.kernel.org \
--cc=quozl@laptop.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.