Re: [E1000-devel] Clock frequency for 82579V

[Alexander I. <sh...@se...>]

On Mon, Nov 21, 2016 at 01:23:56AM +0300, Alexander Inyukhin wrote:
> Hi,
> 
> I'm trying to setup PTP on my 82579V, and it seems that clock speed is 3.84 times faster than expected.
> 
> $ phc_ctl /dev/ptp0 -- get wait 1 get
> phc_ctl[33374.657]: clock time is 1479697143.971579879 or Mon Nov 21 05:59:03 2016
> phc_ctl[33375.657]: process slept for 1.000000 seconds
> phc_ctl[33375.657]: clock time is 1479697147.811930581 or Mon Nov 21 05:59:07 2016
> $ python -c "print 1479697147.811930581 - 1479697143.971579879"
> 3.84035086632
> 
> Most likely, this device has 96MHz clock instead of 25MHz (these values
> are taken from ./drivers/net/ethernet/intel/e1000e/netdev.c file).
> How could I fix that?

Looks like 83129b37ef is to blame.
Before this patch e1000_pch2lan devices always have 96MHz clock,
but now the clock speed depends on E1000_TSYNCRXCTL_SYSCFI bit.