K 10
svn:author
V 3
ian
K 8
svn:date
V 27
2017-07-31T01:18:21.580449Z
K 7
svn:log
V 994
Add clock_schedule(), a feature that allows realtime clock drivers to
request that their clock_settime() methods be called at a given offset
from top-of-second.  This adds a timeout_task to the rtc_instance so that
each clock can be separately added to taskqueue_thread with the scheduling
it prefers, instead of looping through all the clocks at once with a
single task on taskqueue_thread.  If a driver doesn't call clock_schedule()
the default is the old behavior: clock_settime() is queued immediately.

The motivation behind this is that I was on the path of adding identical
code to a third RTC driver to figure out a delta to top-of-second and
sleep for that amount of time because writing the the RTC registers resets
the hardware's concept of top-of-second.  (Sometimes it's not top-of-second,
some RTC clocks tick over a half second after you set their time registers.)
Worst-case would be to sleep for almost a full second, which is a rude thing
to do on a shared task queue thread.

END