> -----Original Message----- > From: Richard Cochran <richardcoch...@gmail.com> > Sent: Tuesday, March 30, 2021 10:14 PM > To: Keller, Jacob E <jacob.e.kel...@intel.com> > Cc: linuxptp-devel@lists.sourceforge.net > Subject: Re: [Linuxptp-devel] SyncE support > > On Tue, Mar 30, 2021 at 11:40:42AM -0700, Jacob Keller wrote: > > On 3/22/2021 8:40 AM, Miroslav Lichvar wrote: > > > FWIW, some onboard NICs supported by the e1000e driver can > > > "cross-timestamp" using the Always Running Timer (ART), which should > > > avoid the asymmetry of PCIe. I have not seen any detailed > > > description of how it actually works. > > > > > > > I'm not sure in the e1000e case but in general this is done via PCIe > > Precision Time Measurement extension which allows an end-point device > > that supports the function to setup a transaction that captures the > > device clock and ART value near-simultaneously. > > > > I think the e1000e support might be a variation of this which > > pre-dated the PTM standard and works when the device is a LAN-on- > motherboard. > > My understanding was that the e1000e did in fact implement the newfangled > PCIe thingy. But I could be wrong.
Some Intel I219 adapters embedded in the Sunrise Point PCH (and newer) have the ability to capture the ART along with the PTP clock. But that's not based on PTM, but on the proprietary Hammock Harbor IP triggered from the e1000. You can read about it here: https://www.freepatentsonline.com/y2020/0127861.html Regards Maciek > > Thanks, > Richard > > > _______________________________________________ > Linuxptp-devel mailing list > Linuxptp-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linuxptp-devel Intel Technology Poland sp. z o.o. ul. Sowackiego 173 | 80-298 Gdask | Sd Rejonowy Gdask Pnoc | VII Wydzia Gospodarczy Krajowego Rejestru Sdowego - KRS 101882 | NIP 957-07-52-316 | Kapita zakadowy 200.000 PLN. Ta wiadomo wraz z zacznikami jest przeznaczona dla okrelonego adresata i moe zawiera informacje poufne. W razie przypadkowego otrzymania tej wiadomoci, prosimy o powiadomienie nadawcy oraz trwae jej usunicie; jakiekolwiek przegldanie lub rozpowszechnianie jest zabronione. This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). If you are not the intended recipient, please contact the sender and delete all copies; any review or distribution by others is strictly prohibited. _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
