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From: Jakub Kicinski <kuba@kernel.org>
To: "Köry Maincent" <kory.maincent@bootlin.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>,
	Richard Cochran <richardcochran@gmail.com>,
	andrew@lunn.ch, davem@davemloft.net, f.fainelli@gmail.com,
	hkallweit1@gmail.com, netdev@vger.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>
Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues]
Date: Thu, 2 Mar 2023 09:23:20 -0800	[thread overview]
Message-ID: <20230302092320.6ee8eb6d@kernel.org> (raw)
In-Reply-To: <20230302180616.7bcfc1ef@kmaincent-XPS-13-7390>

On Thu, 2 Mar 2023 18:06:16 +0100 Köry Maincent wrote:
> I have measured it with the Marvell PHY and MACB MAC but it is the contrary on
> my side:
> https://lkml.kernel.org/netdev/20230302113752.057a3213@kmaincent-XPS-13-7390/
> Also PHY default seems more logical as it is nearer to the physical link, but
> still I am interesting by the answer as I am not a PTP expert. Is really PTP
> MAC often more precise than PTP PHY?

Do you happen to have a datasheet for MACB? The time stamping
capability is suspiciously saved in a variable called hw_dma_cap
which may indicate it's a DMA time stamp not a true PTP stamp.

Quite a few NICs/MACs support DMA time stamps because it's far 
easier to take the stamp where the descriptor writing logic is
(DMA block) than take it at the end of the MAC and haul it all 
the way thru the pipeline back to the DMA block.

  reply	other threads:[~2023-03-02 17:23 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14 16:26 [PATCH RFC net-next] net: phy: add Marvell PHY PTP support Russell King
2020-07-15 18:38 ` Andrew Lunn
2020-07-15 18:56   ` Russell King - ARM Linux admin
2020-07-16 11:33     ` Russell King - ARM Linux admin
2020-07-16 20:53       ` Richard Cochran
2020-07-16 20:48 ` Richard Cochran
2020-07-17  7:54   ` Kurt Kanzenbach
2020-07-18  2:24     ` Richard Cochran
2020-07-20 14:21       ` Richard Cochran
2020-07-20 14:37         ` Kurt Kanzenbach
2020-07-26 23:48 ` Russell King - ARM Linux admin
2020-07-29 10:58 ` Russell King - ARM Linux admin
2020-07-29 13:19   ` Richard Cochran
2020-07-29 13:28     ` Russell King - ARM Linux admin
2020-07-29 22:07       ` Russell King - ARM Linux admin
2020-07-29 22:53         ` Vladimir Oltean
2020-07-30 15:53         ` Richard Cochran
2020-07-30 18:38           ` Russell King - ARM Linux admin
2020-07-30 19:32             ` Richard Cochran
2020-07-30 19:44               ` Russell King - ARM Linux admin
2020-07-30 11:06     ` [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues] Russell King - ARM Linux admin
2020-07-30 11:54       ` Russell King - ARM Linux admin
2020-07-30 12:47         ` Russell King - ARM Linux admin
2023-02-27 14:40           ` Köry Maincent
2023-02-27 15:20             ` Russell King (Oracle)
2023-02-27 17:30               ` Köry Maincent
2023-02-27 17:42                 ` Russell King (Oracle)
2023-02-27 19:45               ` Richard Cochran
2023-02-27 20:09                 ` Russell King (Oracle)
2023-02-27 20:19                   ` Richard Cochran
2023-02-28 12:07                     ` Russell King (Oracle)
2023-02-28 13:16                       ` Köry Maincent
2023-02-28 13:36                         ` Russell King (Oracle)
2023-02-28 14:50                           ` Köry Maincent
2023-02-28 15:16                         ` Richard Cochran
2023-02-28 15:33                           ` Andrew Lunn
2023-02-28 21:13                             ` Richard Cochran
2023-02-28 16:27                           ` Russell King (Oracle)
2023-02-28 16:44                             ` Michael Walle
2023-02-28 16:58                               ` Russell King (Oracle)
2023-02-28 20:13                                 ` Michael Walle
2023-02-28 21:11                                   ` Richard Cochran
2023-02-28 21:24                             ` Richard Cochran
2023-02-28 22:26                             ` Jakub Kicinski
2023-02-28 22:40                               ` Russell King (Oracle)
2023-02-28 22:59                                 ` Jakub Kicinski
2023-03-01 16:04                                   ` Köry Maincent
2023-03-02  4:36                                     ` Richard Cochran
2023-03-02 11:49                                       ` Russell King (Oracle)
2023-03-02 16:49                                         ` Jakub Kicinski
2023-03-02 17:06                                           ` Köry Maincent
2023-03-02 17:23                                             ` Jakub Kicinski [this message]
2023-03-03 13:12                                               ` Köry Maincent
2023-03-03 23:28                                                 ` Jakub Kicinski
2023-03-02 17:26                                           ` Russell King (Oracle)
2023-03-03 10:20                                             ` Michael Walle
2023-03-03 13:20                                               ` Andrew Lunn
2023-03-03 13:34                                                 ` Köry Maincent
2023-03-03 13:59                                                   ` Andrew Lunn
2023-03-03 14:03                                                 ` Russell King (Oracle)
2023-03-03 16:34                                                   ` Andrew Lunn
2023-03-03 17:32                                                     ` Richard Cochran
2023-03-03 17:35                                                       ` Richard Cochran
2023-03-03 23:40                                                   ` Jakub Kicinski
2023-03-02 21:28                                           ` Richard Cochran
2023-03-02 21:19                                         ` Richard Cochran
2023-04-27 15:13               ` Köry Maincent
2023-04-27 16:50                 ` Andrew Lunn
2023-04-28  8:51                   ` Köry Maincent
2020-07-30 15:50         ` Richard Cochran
2020-07-31 14:41         ` Andrew Lunn
2023-03-02 10:37   ` [PATCH RFC net-next] net: phy: add Marvell PHY PTP support Köry Maincent
2023-03-02 17:38     ` Russell King (Oracle)
2023-03-02 21:35     ` Richard Cochran

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