On Wed, Oct 13, 2021 at 11:56:00AM +0200, Sebastien Laveze wrote:

My proposal includes handling PHC offset entirely in software. There is
no way (and we agree on this :)) to change the PHC offset without
impacting children virtual clocks.

That means no control over the phase of the output signals.  Super.
 

Done in software, an offset adjustment has no impact at all on virtual
clocks (since it can always be done atomically, not RMW).

So with, no hardware clock phase adjustment and limited frequency
adjustments, 

But you can't make the end users respect that.  In many cases in the
wild, the GM offset changes suddenly for various reasons, and then the
clients slew at max adjustment.  So there is no expectation of
"limited frequency adjustments."

Thanks,
Richard

we believe it can be made fully transparent to virtual
clocks. And that would improve the current limitation of no adjustment
all, and would unblock the support of features like Qbv for devices
with a single clock.

Thanks,
Sebastien