On Thu, May 14, 2020 at 05:09:01PM +0200, Olivier Dautricourt wrote: > My issue is that the default behavior of the stmmac driver is to > set the mac into fine mode which implies to continuously do frequency > adjustment, So if i'm not mistaken using the nullf servo will not address > that issue even if we are not doing explicit clock_adjtime syscalls.
Why not use the external time stamps from your GPS to do one of the following? A) Feed them into a user space PI controller and do frequency correction, or B) Feed the offsets into the hardware PLL (if that is present) using the new PHC ADJ_OFFSET support (found in net-next). I don't see a need for changing any kernel interfaces at all. If you think there is such a need, then you will have to make some kind of argument or justification for it. BTW, support for B has been implemented in linuxptp, and the patches will appear soon. We can also add it into the ts2phc program if you like. Thanks, Richard
