On Thu, 2 Jan 2020 at 18:14, Karel Zak <kzak@xxxxxxxxxx> wrote: > > At first glance it seems hwclock works as expected, I do not see > anything wrong in the output. > > > Demonstration: https://youtu.be/Yx27IH2opEc > > What is hw time before reboot? Can you verify that hwclock reset the > clock? (or is it system reboot?) > > # hwclock -w -v > # hwclock -v > > Do you see anything interesting in dmesg output before reboot and after > hwclock -w? > > Yes, before reboot all look like good: [root@localhost ~]# hwclock -v hwclock from util-linux 2.35-rc1-20-63f8 System Time: 1577977370.909455 Trying to open: /dev/rtc0 Using the rtc interface to the clock. Last drift adjustment done at 1577973311 seconds after 1969 Last calibration done at 1577973311 seconds after 1969 Hardware clock is on UTC time Assuming hardware clock is kept in UTC time. Waiting for clock tick... ...got clock tick Time read from Hardware Clock: 2020/01/02 15:02:52 Hw clock time : 2020/01/02 15:02:52 = 1577977372 seconds since 1969 Time since last adjustment is 4061 seconds Calculated Hardware Clock drift is 0.000000 seconds 2020-01-02 20:02:51.077494+05:00 [root@localhost ~]# hwclock -w -v hwclock from util-linux 2.35-rc1-20-63f8 System Time: 1577977383.789039 Trying to open: /dev/rtc0 Using the rtc interface to the clock. Last drift adjustment done at 1577973311 seconds after 1969 Last calibration done at 1577973311 seconds after 1969 Hardware clock is on UTC time Assuming hardware clock is kept in UTC time. RTC type: 'rtc_cmos' Using delay: 0.500000 seconds missed it - 1577977383.789405 is too far past 1577977383.500000 (0.289405 > 0.001000) 1577977384.500000 is close enough to 1577977384.500000 (0.000000 < 0.002000) Set RTC to 1577977384 (1577977383 + 1; refsystime = 1577977383.000000) Setting Hardware Clock to 15:03:04 = 1577977384 seconds since 1969 ioctl(RTC_SET_TIME) was successful. Not adjusting drift factor because the --update-drift option was not used. New /etc/adjtime data: 0.000000 1577977383 0.000000 1577977383 UTC [root@localhost ~]# hwclock -v hwclock from util-linux 2.35-rc1-20-63f8 System Time: 1577977389.540630 Trying to open: /dev/rtc0 Using the rtc interface to the clock. Last drift adjustment done at 1577977383 seconds after 1969 Last calibration done at 1577977383 seconds after 1969 Hardware clock is on UTC time Assuming hardware clock is kept in UTC time. Waiting for clock tick... ...got clock tick Time read from Hardware Clock: 2020/01/02 15:03:10 Hw clock time : 2020/01/02 15:03:10 = 1577977390 seconds since 1969 Time since last adjustment is 7 seconds Calculated Hardware Clock drift is 0.000000 seconds 2020-01-02 20:03:09.718222+05:00 But after reboot, the hwtime is reset: === Reboot === [root@localhost ~]# hwclock -v hwclock from util-linux 2.35-rc1-20-63f8 System Time: 1576407103.342223 Trying to open: /dev/rtc0 Using the rtc interface to the clock. Last drift adjustment done at 1577977383 seconds after 1969 Last calibration done at 1577977383 seconds after 1969 Hardware clock is on UTC time Assuming hardware clock is kept in UTC time. Waiting for clock tick... ...got clock tick Time read from Hardware Clock: 2019/01/01 00:05:31 Hw clock time : 2019/01/01 00:05:31 = 1546301131 seconds since 1969 Time since last adjustment is -31676252 seconds Calculated Hardware Clock drift is 0.000000 seconds 2019-01-01 05:05:30.170661+05:00 [root@localhost ~]# date Sun 15 Dec 2019 03:52:01 PM +05 Demonstration: https://youtu.be/X0w2hbAmKmM -- Best Regards, Mike Gavrilov.
