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From: "Keller, Jacob E" <jacob.e.keller@intel.com>
To: Richard Cochran <richardcochran@gmail.com>,
	"Machnikowski, Maciej" <maciej.machnikowski@intel.com>
Cc: "cong.wang@bytedance.com" <cong.wang@bytedance.com>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"gustavoars@kernel.org" <gustavoars@kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"colin.king@canonical.com" <colin.king@canonical.com>,
	"intel-wired-lan@lists.osuosl.org"
	<intel-wired-lan@lists.osuosl.org>,
	"nikolay@nvidia.com" <nikolay@nvidia.com>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	"kuba@kernel.org" <kuba@kernel.org>,
	"shuah@kernel.org" <shuah@kernel.org>,
	"davem@davemloft.net" <davem@davemloft.net>
Subject: RE: [Intel-wired-lan] [RFC net-next 1/7] ptp: Add interface for acquiring DPLL state
Date: Wed, 18 Aug 2021 18:14:13 +0000	[thread overview]
Message-ID: <CO1PR11MB5089A30F5681B860B3F9F96CD6FF9@CO1PR11MB5089.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20210818170259.GD9992@hoboy.vegasvil.org>



> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Richard Cochran
> Sent: Wednesday, August 18, 2021 10:03 AM
> To: Machnikowski, Maciej <maciej.machnikowski@intel.com>
> Cc: cong.wang@bytedance.com; arnd@arndb.de; gustavoars@kernel.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org;
> colin.king@canonical.com; intel-wired-lan@lists.osuosl.org; nikolay@nvidia.com;
> linux-kselftest@vger.kernel.org; kuba@kernel.org; shuah@kernel.org;
> davem@davemloft.net
> Subject: Re: [Intel-wired-lan] [RFC net-next 1/7] ptp: Add interface for acquiring
> DPLL state
> 
> On Tue, Aug 17, 2021 at 09:41:49AM +0000, Machnikowski, Maciej wrote:
> 
> > The logic behind adding the DPLL state to the PTP subsystem is that SyncE DPLL
> on Network adapters, in most cases, drive the PTP timer.
> 
> So what?  The logic in the HW has nothing to do with the proper user
> space interfaces.  For example, we have SO_TIMESTAMPING and PHC as
> separate APIs, even though HW devices often implement both.
> 
> > Having access to it in the PTP subsystem is beneficial, as Telco
> > standards, like G.8275.1/2, require a different behavior depending
> > on the SyncE availability and state.
> 
> Right, but this does say anything about the API.
> 
> > Multiport adapters use a single PLL to drive all ports. If we add
> > the PLL interface to the PTP device - a tool that would implement
> > support for Telco standards would have a single source of
> > information about the presence and state of physical sync.
> 
> Not really.  Nothing guarantees a sane mapping from MAC to PHC.  In
> many systems, there a many of each.
> 

Well, I think the point of placing it in the PTP subsystem is that there is a sane mapping between PHC <-> DPLL. There's only one DPLL for the PHC.

Thanks,
Jake

  reply	other threads:[~2021-08-18 18:14 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16 16:07 [RFC net-next 0/7] Add basic SyncE interfaces Arkadiusz Kubalewski
2021-08-16 16:07 ` [RFC net-next 1/7] ptp: Add interface for acquiring DPLL state Arkadiusz Kubalewski
2021-08-16 23:54   ` Richard Cochran
2021-08-17  9:41     ` Machnikowski, Maciej
2021-08-18 17:02       ` Richard Cochran
2021-08-18 18:14         ` Keller, Jacob E [this message]
2021-08-18 22:36         ` Machnikowski, Maciej
2021-08-19 15:34           ` Richard Cochran
2021-08-19 15:40             ` Machnikowski, Maciej
2021-08-20 15:55               ` Richard Cochran
2021-08-20 18:30                 ` Machnikowski, Maciej
2021-08-22  1:50                   ` Richard Cochran
2021-08-22  2:30                   ` Richard Cochran
2021-08-23  8:29                     ` Machnikowski, Maciej
2021-08-30 21:06                   ` Richard Cochran
2021-08-31  9:29                     ` Machnikowski, Maciej
2021-08-16 16:07 ` [RFC net-next 2/7] selftests/ptp: Add usage of PTP_DPLL_GETSTATE ioctl in testptp Arkadiusz Kubalewski
2021-08-16 23:54   ` Richard Cochran
2021-08-16 16:07 ` [RFC net-next 3/7] ice: add get_dpll_state ptp interface usage Arkadiusz Kubalewski
2021-08-16 16:07 ` [RFC net-next 4/7] net: add ioctl interface for recover reference clock on netdev Arkadiusz Kubalewski
2021-08-16 19:46   ` Arnd Bergmann
2021-08-17 10:35     ` Kubalewski, Arkadiusz
2021-08-22  1:25   ` Richard Cochran
2021-08-16 16:07 ` [RFC net-next 5/7] selftests/net: Add test app for SIOC{S|G}SYNCE Arkadiusz Kubalewski
2021-08-16 16:07 ` [RFC net-next 6/7] ice: add SIOC{S|G}SYNCE interface usage to recover reference signal Arkadiusz Kubalewski
2021-08-16 16:07 ` [RFC net-next 7/7] ice: add sysfs interface to configure PHY recovered " Arkadiusz Kubalewski
2021-08-18 17:05 ` [RFC net-next 0/7] Add basic SyncE interfaces Richard Cochran
2021-08-18 17:08 ` Richard Cochran

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