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authorDavid S. Miller <davem@davemloft.net>2018-11-11 17:57:54 -0800
committerDavid S. Miller <davem@davemloft.net>2018-11-11 17:57:54 -0800
commit2b9b7502dfcb6169dbf3359702953bf756b4e273 (patch)
tree58ab22096d49de6a0e049cf1267edc34b82916dc /drivers/net/ethernet/intel/igb
parentPCI: add USR vendor id and use it in r8169 and w6692 driver (diff)
parentLinux 4.20-rc2 (diff)
downloadlinux-dev-2b9b7502dfcb6169dbf3359702953bf756b4e273.tar.xz
linux-dev-2b9b7502dfcb6169dbf3359702953bf756b4e273.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'drivers/net/ethernet/intel/igb')
-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 8c1833a157d3..fd3071f55bd3 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -53,13 +53,15 @@
* 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)