On 11/23/2017 07:53 AM, Russell King - ARM Linux wrote: > On Thu, Nov 23, 2017 at 01:04:51PM +0100, Alexandre Belloni wrote: >> 8< >> But nothing prevents you from using hwclock every 11 minutes from >> userspace. I really don't think this should be done from the kernel. > > It's not just about running hwclock every 11 minutes. It's about > running hwclock when NTP sync'd. If the local clock is not sync'd > you don't want to be running hwclock, especially if you've trimmed > the RTC. So merely throwing hwclock -uw into a cron job really > doesn't solve it. > > A way around that would be to install adjtimex, so that the kernel's > NTP flags can be read out. However, that comes with its own set of > problems. > > On Debian, installing adjtimex will disrupt the timekeeping because > of the post-install scripts debian runs. It seems Debian assumes > that if you install something, it has the right to modify the system > timekeeping parameters immediately, screwing up ntpd in the process, > if it's running. The thought that you're installing adjtimex because > you want to _inspect_ the kernel ntp parameters is not one that > Debian folk appear to have considered as being a reason for installing > the package. > IMO, adjtimex is broken anyway. Use ntptime, it should be included in the ntp package: $ /usr/sbin/ntptime | grep status status 0x40 (UNSYNC), 'ntptime -f ppm' allows correcting the system clock. So adjtimex really isn't needed anymore.
