From: Bernd Faust berndfaust@gmail.com
[ Upstream commit 5313eeccd2d7f486be4e5c7560e3e2be239ec8f7 ]
After an upgrade to Linux kernel v4.x the hardware timestamps of the 82579 Gigabit Ethernet Controller are different than expected. The values that are being read are almost four times as big as before the kernel upgrade.
The difference is that after the upgrade the driver sets the clock frequency to 25MHz, where before the upgrade it was set to 96MHz. Intel confirmed that the correct frequency for this network adapter is 96MHz.
Signed-off-by: Bernd Faust berndfaust@gmail.com Acked-by: Sasha Neftin sasha.neftin@intel.com Acked-by: Jacob Keller jacob.e.keller@intel.com Tested-by: Aaron Brown aaron.f.brown@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/net/ethernet/intel/e1000e/netdev.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 081dad4e0178..3df8366a8356 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -3507,6 +3507,12 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca)
switch (hw->mac.type) { case e1000_pch2lan: + /* Stable 96MHz frequency */ + incperiod = INCPERIOD_96MHz; + incvalue = INCVALUE_96MHz; + shift = INCVALUE_SHIFT_96MHz; + adapter->cc.shift = shift + INCPERIOD_SHIFT_96MHz; + break; case e1000_pch_lpt: /* On I217, the clock frequency is 25MHz or 96MHz as * indicated by the System Clock Frequency Indication