> From: Intel-wired-lan [mailto:intel-wired-lan-boun...@osuosl.org] On > Behalf Of Miroslav Lichvar > Sent: Friday, October 26, 2018 10:13 AM > To: netdev@vger.kernel.org > Cc: intel-wired-...@lists.osuosl.org; Richard Cochran > <richardcoch...@gmail.com>; Thomas Gleixner <t...@linutronix.de> > Subject: [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC > timecounter update interval > > The timecounter needs to be updated at least once per ~550 seconds in > order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old > timestamp. > > Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"), > scheduling of delayed work seems to be less accurate and a requested > delay of 540 seconds may actually be longer than 550 seconds. Also, the > PHC may be adjusted to run up to 6% faster than real time and the system > clock up to 10% slower. Shorten the delay to 360 seconds to be sure the > timecounter is updated in time. > > This fixes an issue with HW timestamps on 82580/I350/I354 being off by > ~1100 seconds for few seconds every ~9 minutes. > > Cc: Jacob Keller <jacob.e.kel...@intel.com> > Cc: Richard Cochran <richardcoch...@gmail.com> > Cc: Thomas Gleixner <t...@linutronix.de> > Signed-off-by: Miroslav Lichvar <mlich...@redhat.com> > --- > drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) >
Tested-by: Aaron Brown <aaron.f.br...@intel.com>
