Received-SPF: pass (google.com: domain of linux-kernel+bounces-125115-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Date: Fri, 29 Mar 2024 08:10:58 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: =?UTF-8?B?UGF3ZcWC?= Dembicki <paweldembicki@gmail.com>
Cc: netdev@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>, Heiner Kallweit
 <hkallweit1@gmail.com>, Russell King <linux@armlinux.org.uk>, "David S.
 Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo
 Abeni <pabeni@redhat.com>, Stefan Eichenberger <eichest@gmail.com>, Dimitri
 Fedrau <dima.fedrau@gmail.com>, Kory Maincent <kory.maincent@bootlin.com>,
 Maxime Chevallier <maxime.chevallier@bootlin.com>, Shay Agroskin
 <shayagr@amazon.com>, Ahmed Zaki <ahmed.zaki@intel.com>,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v2 2/3] net: ethtool: Add impedance mismatch
 result code to cable test
Message-ID: <20240329081058.15ee0f1d@kernel.org>
In-Reply-To: <CAJN1KkxcX9dfhMVvQCFLosTgO5U2tAjvHEO-prViSacOB6DQRg@mail.gmail.com>
References: <20240327162918.2426792-1-paweldembicki@gmail.com>
	<20240327162918.2426792-2-paweldembicki@gmail.com>
	<20240328190226.7aab8b76@kernel.org>
	<CAJN1KkxcX9dfhMVvQCFLosTgO5U2tAjvHEO-prViSacOB6DQRg@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

On Fri, 29 Mar 2024 10:31:10 +0100 Pawe=C5=82 Dembicki wrote:
> > I'm not a cable expert but going purely by the language
> > abnormal !=3D mismatch. Mismatch indicates there are two
> > values we are comparing. =20
>=20
> Impedance mismatch can be detected because some parts of the cable may
> have different (abnormal) impedance, causing reflections at those
> points. Ethernet cables should have a characteristic impedance of 100
> Ohms, so any mismatch from this value is considered abnormal.

I see, makes sense.

> I can provide a rephrased version if the commit description was not
> detailed enough.

That'd be great. Or maybe even better a short comment above the enum
entry?