Replace struct timeval with struct timespec as the main data type for
timestamps. This will allow the NTP code to work with timestamps in
nanosecond resolution.
Timeout ID of zero can be now safely used to indicate that the timer is
not running. Remove the extra timer_running variables that were
necessary to track that.
The system drivers may implement their own slewing which the generic
driver can use to slew faster than the maximum frequency the driver is
allowed to set directly.
Different systems may consider different time values to be valid.
Don't exit on settimeofday()/adjtimex() error in case the check in
UTI_IsTimeOffsetSane() isn't restrictive enough.
This will be used to set the kernel adjtimex() variables to allow other
applications running on the system to know if the system clock is
synchronized and the estimated error and the maximum error.
Add a new change type and use it when an unexpected time jump is
detected in the scheduler to reset reference times, offset and slewing,
NCR instances (with their polling interval), synchronization status, and
drop all sourcestats, manual, refclock and RTC samples.
This should make the recovery more graceful if the estimated jump has a
large error (e.g. select didn't timeout, or after system suspend).
There is no need to try to correct offsets below the specified minimum
(1 nanosecond), let the clock drift away after crossing zero offset and
avoid unnecessary updates.
With the generic driver, the maxslewrate directive sets the maximum
frequency offset that the driver is allowed to use to slew the time. By
default, it's set to 83333.333 (1/12). This is identical to what Linux
fast slewing used to use.
This driver is intended to complete system-specific drivers that don't
have implemented all required driver functionality. Currently, it
implements offset functions working on top of system-specific frequency
functions. Offsets are corrected by changing frequency, similarly to
fast slewing implemented in the Linux driver.
