On Thu, Jun 06, 2019 at 04:40:19PM +0300, Vladimir Oltean wrote:

Plain and simply because it doesn't work very well.
Even phc2sys from the system clock to the hardware (no timestamps
involved) has trouble staying put (under 1000 ns offset).
And using the hardware-corrected timestamps triggers a lot of clockchecks.

It sounds like a bug in reading or adjusting the HW clock.  Is the HW
clock stable when you don't adjust its frequency?

Thanks,
Richard