From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keller, Jacob E Date: Wed, 20 Apr 2016 17:56:32 +0000 Subject: [Intel-wired-lan] [PATCH v3] e1000e: don't modify SYSTIM registers during SIOCSHWTSTAMP ioctl In-Reply-To: <20160415224127.4172-1-jacob.e.keller@intel.com> References: <20160415224127.4172-1-jacob.e.keller@intel.com> Message-ID: <1461174992.1546.22.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On Fri, 2016-04-15 at 15:41 -0700, Jacob Keller wrote: > The e1000e_config_hwtstamp function was incorrectly resetting the > SYSTIM > registers every time the ioctl was being run. If you happened to be > running ptp4l and lost the PTP connect (removing cable, or blocking > the > UDP traffic for example), then ptp4l will eventually perform a > restart > which involves re-requesting timestamp settings. In e1000e this has > the > unfortunate and incorrect result of resetting SYSTIME to the kernel > time. Since kernel time is usually in UTC, and PTP time is in TAI, > this > results in the leap second being re-applied. > > Fix this by extracting the SYSTIME reset out into its own function, > e1000e_ptp_reset, which we call during reset to restore the hardware > registers. This function will (a) restart the timecounter based on > the > new system time, (b) restore the previous PPB setting, and (c) > restore > the previous hwtstamp settings. > > In order to perform (b), I had to modify the adjfreq ptp function > pointer to store the old delta each time it is called. This also has > the > side effect of restoring the correct base timinca register correctly. > The driver does not need to explicitly zero the ptp_delta variable > since > the entire adapter structure comes zero-initialized. > > Reported-by: Brian Walsh > Signed-off-by: Jacob Keller > Unfortunately, Todd Fujinaka found an issue with this patch on e1000e devices which do not support timestamping. I forgot to add a check to the HW_TIMESTAMP flag. I cleaned up a few other minor things as well in v4. Sorry (again) for the thrash, we'll get this worked out. Jeff, can you drop this patch from the queue a v4 is incoming. Regards, Jake