All of
 help / color / mirror / Atom feed
From: Andrew Lunn <>
To: Kishon Vijay Abraham I <>
Cc: Steen Hegelund <>,
	Vinod Koul <>,
	Alexandre Belloni <>,
	Lars Povlsen <>,
	Bjarni Jonasson <>,
	Microchip UNG Driver List <>,,
Subject: Re: [PATCH v14 2/4] phy: Add media type and speed serdes configuration interfaces
Date: Mon, 15 Feb 2021 15:07:45 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Mon, Feb 15, 2021 at 05:25:10PM +0530, Kishon Vijay Abraham I wrote:
> Okay. Is it going to be some sort of manual negotiation where the
> Ethernet controller invokes set_speed with different speeds? Or the
> Ethernet controller will get the speed using some out of band mechanism
> and invokes set_speed once with the actual speed?

Hi Kishon

There are a few different mechanism possible.

The SFP has an EEPROM which contains lots of parameters. One is the
maximum baud rate the module supports. PHYLINK will combine this
information with the MAC capabilities to determine the default speed.

The users can select the mode the MAC works in, e.g. 1000BaseX vs
2500BaseX, via ethtool -s. Different modes needs different speeds.

Some copper PHYs will change there host side interface baud rate when
the media side interface changes mode. 10GBASE-X for 10G copper,
5GBase-X for 5G COPPER, 2500Base-X for 2.5G copper, and SGMII for
old school 10/100/1G Ethernet.

Mainline Linux has no support for it, but some 'vendor crap' will do a
manual negotiation, simply trying different speeds and see if the
SERDES establishes link. There is nothing standardised for this, as
far as i know.


  reply	other threads:[~2021-02-15 14:09 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10  8:52 [PATCH v14 0/4] Adding the Sparx5 Serdes driver Steen Hegelund
2021-02-10  8:52 ` [PATCH v14 1/4] dt-bindings: phy: Add sparx5-serdes bindings Steen Hegelund
2021-02-10  8:52 ` [PATCH v14 2/4] phy: Add media type and speed serdes configuration interfaces Steen Hegelund
2021-02-10 23:32   ` David Miller
2021-02-12 11:23     ` Steen Hegelund
2021-02-12 11:32   ` Kishon Vijay Abraham I
2021-02-12 13:05     ` Steen Hegelund
2021-02-15 11:55       ` Kishon Vijay Abraham I
2021-02-15 14:07         ` Andrew Lunn [this message]
2021-02-16  8:37           ` Steen Hegelund
2021-02-16 10:24             ` Kishon Vijay Abraham I
2021-02-18 14:45               ` Steen Hegelund
2021-02-10  8:52 ` [PATCH v14 3/4] phy: Add Sparx5 ethernet serdes PHY driver Steen Hegelund
2021-02-10  8:52 ` [PATCH v14 4/4] arm64: dts: sparx5: Add Sparx5 serdes driver node Steen Hegelund

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \

* 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.