[LinuxPPS] PPS next steps...

[George Spelvin]

I need to test things like the poll function and fasync.
The patches I posted run ntpd just fine (x86_64, at least), but
that doesn't test the more obscure stuff.

Given a working poll function, it would be nice to change the kernel
API to handle the timeout in user space using poll() or select() and
simplfy the kernel fetch IOCTL.

I'm also thinking about a text form to be delivered when
reading from the file.  the main problem is that the format in
/sys/class/pps/pps%d/{assert,clear} provides no way to distinguish assert
from clear edges.  Maybe a leading sign on the sequence number?

Or just a Plan 9 style whitespace-separated line.
assert <seq> <time>.<frac>
clear <seq> <time>.<frac>