Re: [Intel-wired-lan] [PATCH] e1000e: fix timing for 82579 Gigabit Ethernet controller

[Neftin, Sasha]

On 2/26/2017 11:08, Neftin, Sasha wrote:
> On 2/19/2017 14:55, Neftin, Sasha wrote:
> > 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@xxxxxxxxx>
> > > ---
> > >   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@xxxxxxxxxxxxxxxx
> > > 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
> Hello,
>
> During last couple of weeks I saw few  complaints from community on 
> same timing problem with 82579. I will double check clock definition 
> with HW architecture.
>
> Sasha
>
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan@xxxxxxxxxxxxxxxx
> http://lists.osuosl.org/mailman/listinfo/intel-wired-lan

I've double checked - 82579 support 96MHz frequency only. So, let's 
accept this suggestion to upstream.

Ack.