On Tue. 12 Jan 2021 at 02:11, Richard Cochran <richardcochran@xxxxxxxxx> wrote: > > On Sun, Jan 10, 2021 at 09:49:03PM +0900, Vincent Mailhol wrote: > > * The hardware rx timestamp of a local loopback message is the > > hardware tx timestamp. This means that there are no needs to > > implement SOF_TIMESTAMPING_TX_HARDWARE for CAN sockets. > > I can't agree with that statement. The local loopback is a special > "feature" of CAN sockets, and some programs turn it off. Furthermore, > requiring user space to handle CAN sockets differently WRT Tx time > stamps is user-unfriendly. So I would strongly support adding > SOF_TIMESTAMPING_TX_HARDWARE to the CAN layer in the future. > > (This isn't a criticism of the current patch, though.) Fair enough. Implementing SOF_TIMESTAMPING_TX_HARDWARE would result into having the timestamp being duplicated for the loopback frames but allowing existing programs to work as with no modifications is a good enough reason. Out of curiosity, which programs do you use? I guess wireshark but please let me know if you use any other programs (I just use to write a small C program to do the stuff). Mark: do you want me to send a v4 of that patch with above comment removed or can you directly do the change in your testing branch? Yours sincerely, Vincent
