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authorThomas Bogendoerfer <tbogendoerfer@suse.de>2018-12-07 13:19:04 +0100
committerThomas Bogendoerfer <tbogendoerfer@suse.de>2018-12-07 13:20:20 +0100
commit19777567ce7fe31f6c3e12f171fa6725c1d4581c (patch)
tree4c7fb962cd706236fec14df168e6bb4987c34e40
parentb086cc79b4138e21b4872fc6ab68b355111359d8 (diff)
igb: shorten maximum PHC timecounter update interval
(bsc#1117495). suse-commit: 96b7edeaf486fd6aac55715c66224112699d332f
-rw-r--r--drivers/net/ethernet/intel/igb/igb_ptp.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 295d27f33104..db7b75c6ca73 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -67,13 +67,15 @@
* 2^40 * 10^-9 / 60 = 18.3 minutes.
*
* SYSTIM is converted to real time using a timecounter. As
- * timecounter_cyc2time() allows old timestamps, the timecounter
- * needs to be updated at least once per half of the SYSTIM interval.
- * Scheduling of delayed work is not very accurate, so we aim for 8
- * minutes to be sure the actual interval is shorter than 9.16 minutes.
+ * timecounter_cyc2time() allows old timestamps, the timecounter needs
+ * to be updated at least once per half of the SYSTIM interval.
+ * Scheduling of delayed work is not very accurate, and also the NIC
+ * clock can be adjusted to run up to 6% faster and the system clock
+ * up to 10% slower, so we aim for 6 minutes to be sure the actual
+ * interval in the NIC time is shorter than 9.16 minutes.
*/
-#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 8)
+#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 6)
#define IGB_PTP_TX_TIMEOUT (HZ * 15)
#define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT)
#define INCVALUE_82576_MASK GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0)