On Tue, Jun 11, 2019 at 09:30:53AM -0400, Sanjay Bhandari wrote: > > How is timestamping GPS PPS different from timestamping external events? > If the driver could provide this feature using the existing > PHC API, I think that would be the best approach. > > It's not. I am saying that to train the PHC to GPS time, we need to > timestamp the GPS PPS with the PHC clock (so we can get the offset to train > the PHC). In the other thread (https://is.gd/qyYHDt) Richard had suggested > that this could be done by feeding GPS PPS into the NIC - IF the NIC was > capable of timestamping external events like this. I was saying that some > NICs can't do this, so it may be done elsewhere (like we do in our FPGA).
What I don't understand is how is your FPGA different from a NIC. In both cases there is a clock which is timestamping packets and PPS on an input pin, right? The clock is provided by the system as a PHC device. Why the PHC cannot support the PTP_EXTTS_REQUEST ioctl? -- Miroslav Lichvar _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
