Messages in this thread | | | Subject | Re: [Intel-wired-lan] [PATCH] e1000e: fix timing for 82579 Gigabit Ethernet controller | From | "Neftin, Sasha" <> | Date | Sun, 19 Feb 2017 14:55:06 +0200 |
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On 2/16/2017 20:42, Bernd Faust wrote: > 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> > --- > 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 7017281..8b7113d 100644 > --- a/drivers/net/ethernet/intel/e1000e/netdev.c > +++ b/drivers/net/ethernet/intel/e1000e/netdev.c > @@ -3511,6 +3511,12 @@ 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: > if (er32(TSYNCRXCTL) & E1000_TSYNCRXCTL_SYSCFI) { > /* Stable 96MHz frequency */ > -- > 2.7.4 > _______________________________________________ > Intel-wired-lan mailing list > Intel-wired-lan@lists.osuosl.org > http://lists.osuosl.org/mailman/listinfo/intel-wired-lan
Hello,
e1000_pch2lan mac type corresponds to 82579LM and 82579V network adapters. System clock frequency indication (SYSCFI) for these devices supports both 25MHz and 96MHz frequency. By default TSYNCRXCTL.SYSCFI is set to 1 and that means 96MHz frequency is picked.
It is better to keep the current implementation as it covers all options.
Thanks,
Sasha
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