From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miroslav Lichvar Date: Fri, 5 Oct 2018 17:35:29 +0200 Subject: [Intel-wired-lan] Periodic jumps of PHC on I350 Message-ID: <20181005153529.GK19804@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: I'm observing a weird issue with the PTP clock on the I350. Every ~9.2 minutes (which coincides with a half of the 40-bit SYSTIM overflow) it jumps about 1100 seconds back and then 8 seconds later it jumps ahead to where it was supposed to be. >From ptp4l output: ptp4l[1700.796]: master offset 126 s2 freq -14982 path delay 45720 ptp4l[1701.796]: clockcheck: clock jumped backward or running slower than expected! ptp4l[1701.796]: master offset -1099511626698 s0 freq -14982 path delay 45720 ptp4l[1701.796]: port 1: SLAVE to UNCALIBRATED on SYNCHRONIZATION_FAULT ptp4l[1702.796]: master offset -1099511626796 s0 freq -14982 path delay 45720 ptp4l[1703.796]: master offset -1099511621597 s0 freq -14982 path delay 45664 ptp4l[1704.796]: master offset -1099511625711 s2 freq -62499999 path delay 45720 ptp4l[1704.796]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED ptp4l[1705.796]: master offset -1099449150078 s2 freq -62499999 path delay 45902 ptp4l[1706.796]: master offset -1099386663207 s2 freq -62499999 path delay 45561 ptp4l[1707.796]: master offset -1099324177805 s2 freq -62499999 path delay 45561 ptp4l[1708.796]: master offset -1099261696997 s2 freq -62499999 path delay 45256 ptp4l[1709.796]: clockcheck: clock jumped forward or running faster than expected! ptp4l[1709.796]: master offset 312422909 s0 freq -62499999 path delay 45256 I see it on four different machines (three have I350, one I354). I've tried 4.19-rc6 and few different versions down to 4.13. All show this behavior. Any ideas what could be wrong? -- Miroslav Lichvar