From: Richard Cochran <richardcochran@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>,
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,
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 17:58:41 -0800 [thread overview]
Message-ID: <20220309015841.GC24366@hoboy.vegasvil.org> (raw)
In-Reply-To: <20220309014647.GB24366@hoboy.vegasvil.org>
On Tue, Mar 08, 2022 at 05:46:47PM -0800, Richard Cochran wrote:
> The problem with uncorrected PHY time stamps is that they affect the
> boundary point between the node and the network. A static error there
> will create a path asymmetry that can neither be measured nor
> corrected by the PTP, and a variable error degrades the time signal.
And FWIW, the imperfections in the cable *also* introduce path
asymmetry and thus uncorrected offsets. The twisted pairs are never
exactly the same length in both directions, for example.
However the PHY delays can be in the microseconds, but cable delay
deltas in the nanoseconds, so correcting PHY delay is much more
important.
Thanks,
Richard
next prev parent reply other threads:[~2022-03-09 1:58 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
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 [this message]
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
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=20220309015841.GC24366@hoboy.vegasvil.org \
--to=richardcochran@gmail.com \
--cc=Divya.Koppera@microchip.com \
--cc=Madhuri.Sripada@microchip.com \
--cc=Manohar.Puri@microchip.com \
--cc=UNGLinuxDriver@microchip.com \
--cc=andrew@lunn.ch \
--cc=davem@davemloft.net \
--cc=devicetree@vger.kernel.org \
--cc=hkallweit1@gmail.com \
--cc=horatiu.vultur@microchip.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=netdev@vger.kernel.org \
--cc=robh+dt@kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).