From: Andrew Lunn <andrew@lunn.ch>
To: Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: Divya.Koppera@microchip.com, netdev@vger.kernel.org,
hkallweit1@gmail.com, linux@armlinux.org.uk, davem@davemloft.net,
kuba@kernel.org, robh+dt@kernel.org, devicetree@vger.kernel.org,
richardcochran@gmail.com, linux-kernel@vger.kernel.org,
UNGLinuxDriver@microchip.com, Madhuri.Sripada@microchip.com,
Manohar.Puri@microchip.com
Subject: Re: [PATCH net-next 2/3] dt-bindings: net: micrel: Configure latency values and timestamping check for LAN8814 phy
Date: Tue, 8 Mar 2022 19:10:12 +0100 [thread overview]
Message-ID: <YiecBKGhVui1Gtb/@lunn.ch> (raw)
In-Reply-To: <20220308154345.l4mk2oab4u5ydn5r@soft-dev3-1.localhost>
> > So this is a function of the track length between the MAC and the PHY?
>
> Nope.
> This latency represents the time it takes for the frame to travel from RJ45
> module to the timestamping unit inside the PHY. To be more precisely,
> the timestamping unit will do the timestamp when it detects the end of
> the start of the frame. So it represents the time from when the frame
> reaches the RJ45 to when the end of start of the frame reaches the
> timestamping unit inside the PHY.
I must be missing something here. How do you measure the latency
difference for a 1 meter cable vs a 100m cable? Does 100m cable plus
1cm of track from the RJ45 to the PHY make a difference compared to
100m cable plus 1.5cm of track? Isn't this error all just in the
noise?
Andrew
next prev parent reply other threads:[~2022-03-08 18:10 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-04 9:34 [PATCH net-next 0/3] Add support for 1588 in LAN8814 Divya Koppera
2022-03-04 9:34 ` [PATCH net-next 1/3] net: phy: micrel: Fix concurrent register access Divya Koppera
2022-03-04 9:34 ` [PATCH net-next 2/3] dt-bindings: net: micrel: Configure latency values and timestamping check for LAN8814 phy Divya Koppera
2022-03-04 12:50 ` Andrew Lunn
2022-03-04 13:55 ` Richard Cochran
2022-03-07 5:02 ` Divya.Koppera
2022-03-07 4:40 ` Divya.Koppera
2022-03-07 13:08 ` Andrew Lunn
2022-03-08 10:05 ` Divya.Koppera
2022-03-08 13:54 ` Andrew Lunn
2022-03-08 14:54 ` Richard Cochran
2022-03-08 15:43 ` Horatiu Vultur
2022-03-08 18:10 ` Andrew Lunn [this message]
2022-03-08 22:14 ` Horatiu Vultur
2022-03-08 23:36 ` Andrew Lunn
2022-03-09 1:46 ` Richard Cochran
2022-03-09 1:58 ` Richard Cochran
2022-03-09 13:24 ` Horatiu Vultur
2022-03-09 14:55 ` Russell King (Oracle)
2022-03-09 19:52 ` Richard Cochran
2022-03-11 14:28 ` Horatiu Vultur
2022-03-11 15:08 ` Richard Cochran
2022-03-12 19:36 ` Allan W. Nielsen
2022-03-13 2:41 ` Richard Cochran
2022-03-13 4:04 ` Richard Cochran
2022-03-11 15:21 ` Woojung.Huh
2022-03-12 2:48 ` Richard Cochran
2022-03-12 20:04 ` Andrew Lunn
2022-03-13 2:46 ` Richard Cochran
2022-03-13 15:07 ` Andrew Lunn
2022-03-13 19:37 ` Allan W. Nielsen
2022-03-13 20:03 ` Richard Cochran
2022-03-13 20:07 ` Richard Cochran
2022-03-11 14:07 ` Horatiu Vultur
2022-03-07 21:33 ` Rob Herring
2022-03-04 9:34 ` [PATCH net-next 3/3] net: phy: micrel: 1588 support " Divya Koppera
2022-03-04 13:06 ` Andrew Lunn
2022-03-07 4:58 ` Divya.Koppera
2022-03-07 13:19 ` Andrew Lunn
2022-03-04 13:46 ` Kurt Kanzenbach
2022-03-04 13:57 ` Richard Cochran
2022-03-04 12:50 ` [PATCH net-next 0/3] Add support for 1588 in LAN8814 patchwork-bot+netdevbpf
2022-03-04 13:06 ` Andrew Lunn
2022-03-04 13:21 ` David Miller
2022-03-04 13:47 ` Andrew Lunn
2022-03-04 14:37 ` David Miller
2022-03-04 14:06 ` Richard Cochran
2022-03-04 14:17 ` Andrew Lunn
2022-03-04 15:42 ` Richard Cochran
2022-03-17 12:16 ` Michael Walle
2022-03-17 14:05 ` Allan W. Nielsen
2022-03-17 14:38 ` Andrew Lunn
2022-03-17 19:30 ` Allan W. Nielsen
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