[Intel-wired-lan] X710-T4L: 5Gb support for IEEE1588

[Alex Sergeev]

Thanks for quick response and the fix!

Would it be backported to standalone drivers, or previous kernel versions
(e.g. 5.4), too?

Thanks,
Alex Sergeev


On Fri, May 7, 2021 at 10:35 AM Jesse Brandeburg <jesse.brandeburg at intel.com>
wrote:

> Alex Sergeev wrote:
>
> > Hello,
> >
> > I got forwarded here by folks at e1000-devel at .
> >
> > We have tried to use PTP with X710-T4L and 5Gb link, and encountered
> > clockcheck problem in phc2sys:
> >
> > Apr 30 22:57:36 budtb phc2sys[5940]: [50.569] clockcheck: clock jumped
> > forward or running faster than expected!
> >
> > After further code examination, it turned out that 5Gb case is not
> handled
> > in i40e_ptp.c
> >
> > Here's the naive version of the patch that fixed the problem for us:
> >
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
> > b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
> > index f1f6fc3744e9..5747b652ee9e 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
> > @@ -12,12 +12,13 @@
> >   *
> >   * Much like the 82599, the update period is dependent upon the link
> speed:
> >   * At 40Gb link or no link, the period is 1.6ns.
> > - * At 10Gb link, the period is multiplied by 2. (3.2ns)
> > + * At 5Gb or 10Gb link, the period is multiplied by 2. (3.2ns)
> >   * At 1Gb link, the period is multiplied by 20. (32ns)
> >   * 1588 functionality is not supported at 100Mbps.
> >   */
> >  #define I40E_PTP_40GB_INCVAL 0x0199999999ULL
> >  #define I40E_PTP_10GB_INCVAL_MULT 2
> > +#define I40E_PTP_5GB_INCVAL_MULT    2
> >  #define I40E_PTP_1GB_INCVAL_MULT 20
> >
> >  #define I40E_PRTTSYN_CTL1_TSYNTYPE_V1
> >  BIT(I40E_PRTTSYN_CTL1_TSYNTYPE_SHIFT)
> > @@ -465,6 +466,9 @@ void i40e_ptp_set_increment(struct i40e_pf *pf)
> >   case I40E_LINK_SPEED_10GB:
> >       mult = I40E_PTP_10GB_INCVAL_MULT;
> >       break;
> > + case I40E_LINK_SPEED_5GB:
> > +     mult = I40E_PTP_5GB_INCVAL_MULT;
> > +     break;
> >   case I40E_LINK_SPEED_1GB:
> >       mult = I40E_PTP_1GB_INCVAL_MULT;
> >       break;
> >
> > What's the process to get it applied upstream?
>
> Hi Alex, that's totally a bug, I've filed an internal bug and we'll be
> providing a patch for this problem shortly.
>
> We'll be sure to credit you for the work to find the bug and proposal
> for the fix!
>
> If you wish to have the patch be authored by you, you're welcome to
> resend to this list with a correctly formatted git patch from
> git-format-patch and git-send-email. If you do nothing, we'll just take
> care of it. :-)
>
> Thanks for the report and the fix!
> Jesse
>
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