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From: Richard Cochran <richardcochran@gmail.com>
To: "Allan W. Nielsen" <allan.nielsen@microchip.com>
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>,
	"Russell King (Oracle)" <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>,
	Divya.Koppera@microchip.com, netdev@vger.kernel.org,
	hkallweit1@gmail.com, 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: Sat, 12 Mar 2022 20:04:12 -0800	[thread overview]
Message-ID: <20220313040412.GA30488@hoboy.vegasvil.org> (raw)
In-Reply-To: <20220312193620.owhfd43dzzxtytgs@den-dk-m31684h>

On Sat, Mar 12, 2022 at 08:36:20PM +0100, Allan W. Nielsen wrote:
> I did skim through the articles, and as you hinted he does find small
> latency differences across different packets. (but as I understood, very
> few PHYs was tested).

There is also previous work cited in those articles.
 
> But this is not really an argument for not having _default_ values
> hard-coded in the driver (or DT, but lets forget about DT for now).

You put them in the DTS.  That means you expect them to need changes.

DTS is the WRONG place for such things.

If your numbers are perfect, then do the corrections in silicon/firmware.

If the numbers aren't 100% perfect, then provide your customers with a
test report providing the recommended numbers.  Include a proper
explanation of the test methodology and assumptions used in your
analysis.  Heck, you can even given them linuxptp config snippets (and
other for other popular PTP stacks, Oregano, ixat, ptpd, etc)

Don't hard code random, changing numbers into kernel drivers.

Thanks,
Richard


  parent reply	other threads:[~2022-03-13  4:04 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
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 [this message]
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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