incorrect date and time waking up from standby

[Tiger25]

On HP Laptop with AMD CPU & graphics. Cinnamon 17.2 64-bit.

Date & time jump 2 days and several hours into future after waking up from standby.

I've rebooted into BIOS it also shows the incorrect time. Resetting it to proper date & time helps for the next boot, but once the laptop wakes up from another standby the date and time are wrong.

Using either Network Time or Local Time in Date and Time Settings still has the problem.

Output from date command also shows the wrong date and time, but the timezone is correct (EDT, New York)

I'm not dual booting Windows so it's not (or are least it shouldn't be) the UTC vs. local time issues I've been seeing on the web.

[Cosmo.]

To find out, where the culprit may be:

Log out and send the pc from the login screen into standby. Check.

[Tiger25]

I've tried 2 things:

1) I change the time zone to central (Chicago), the date & time was correct after waking up. I changed it back to eastern (New York) and the date & time are now also correct after wakeup.

2) I did the complete log-out, standby, wakeup. The date & time is correct.

Looks like so far it's working properly. Maybe the change to Chicago and back to New York reset the settings and now it works fine.

I'll keep testing it. Lets hope the date & time will be correct after an overnight standby.

[Tiger25]

status update:

after the +12 hours of suspend, the unlock screen had a wrong time (about the time the suspend was initiated), but correct date. Once I unlocked the laptop the time updated to the correct one.

After short suspend times (1 minute or so) the time and date is correct.

[Tiger25]

update.

I've tried Ubuntu 15.04; it has the same issue.

I've upgraded Mint 17.2 to Linux kernel 3.19.0-23-generic; the issue still exists.

I found some commands on the web:

ntpdate - it would show the incorrect date & time

sudo ntpdate ntp.ubuntu.com - it would update the date & time to correct; but after waking up from suspend the date & time would be wrong again.

sudo hwclock --debug

--------
hwclock from util-linux 2.20.1
Using /dev interface to clock.
Last drift adjustment done at 1437257298 seconds after 1969
Last calibration done at 1437257298 seconds after 1969
Hardware clock is on UTC time
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
/dev/rtc does not have interrupt functions. Waiting in loop for time from /dev/rtc to change
hwclock: ioctl(RTC_RD_TIME) to /dev/rtc to read the time failed: Invalid argument
...synchronization failed
--------

now I'm wondering if the issue is with hwclock, and/or /dev/rtc

here's another output from hwclock --debug

--------
janek@janek-HP-Pavilion-15-Notebook-PC ~ $ sudo hwclock --debug
[sudo] password for janek:
hwclock from util-linux 2.20.1
Using /dev interface to clock.
Last drift adjustment done at 1437257298 seconds after 1969
Last calibration done at 1437257298 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: 2015/07/29 12:22:16
Hw clock time : 2015/07/29 12:22:16 = 1438172536 seconds since 1969
Wed 29 Jul 2015 08:22:16 AM EDT -0.651639 seconds
janek@janek-HP-Pavilion-15-Notebook-PC ~ $

--------
this time hwclock was able to get the clock tick; but the date & time are still incorrect.