Re: [PATCH v3] power: Add warning message about incorrect systemdate and time after resume when pm_trace is enabled

From: Pavel Machek
Date: Wed Jun 26 2013 - 19:18:16 EST


On Wed 2013-06-26 16:27:35, Shuah Khan wrote:
> pm_trace uses the system's Real Time Clock (RTC) to save the magic number.
> Reason for this is that the RTC is the only reliably available piece of
> hardware during resume operations where a value can be set that will
> survive a reboot.
>
> Consequence is that after a resume (even if it is successful) your system
> clock will have a value corresponding to the magic number instead of the
> correct date/time! It is therefore advisable to use a program like ntp-date
> or rdate to reset the correct date/time from an external time source when
> using this trace option.
>
> There is no run-time message to warn users of the consequences of enabling
> pm_trace. Adding a warning message to pm_trace_store() will serve as a
> reminder to users to set the system date and time after resume.
>
> Signed-off-by: Shuah Khan <shuah.kh@xxxxxxxxxxx>

Acked-by: Pavel Machek <pavel@xxxxxx>

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