On 07/25/14 17:13, Greg Troxel wrote:
Module Name: src Committed By: gdt Date: Fri Jul 25 16:13:21 UTC 2014Modified Files: src/share/man/man4: ucom.4 src/sys/dev/usb: ucom.c Log Message: Add PPS support to ucom(4). This is basically cribbed from regular serial ports, and just adds hooks to call the pps support routines. Also, note in the ucom(4) man page that there is about 1 ms of latency. Discussed on tech-kern in October of 2013, with the only concern being that someone who didn't know what they were doing might set up a stratum 1 server, and that somehow might have worse timekeeping than whatever else that person might have done; the man page comment is a mitigation for this.
latency of 1ms and the same jitter - only ucycom uses interrupt endpoints for data transfer
Nick
