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SubjectRe: [PATCH 2/2][RFC v6] PM / sleep: save/restore RTC time after resumed if pm_trace enabled
Hi all,


On Tue, Nov 08, 2016 at 05:02:14PM +0800, Chen Yu wrote:
> Previously the bogus CMOS RTC sleep time has been ignored if pm_trace
> is enabled, however once the system successfully resumed back,
> any further read to CMOS RTC would return an error. Actually it is
> more user-friendly to bring the system back to normal after resumed.
>
> This patch has registered an pm notifier to restore the RTC to the
> value before been overwitten by pm_trace.
>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Len Brown <lenb@kernel.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Xunlei Pang <xlpang@redhat.com>
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> ---

Please ignore this version for now,
the atomic variable below is unnecessary since
pm_trace has disabled the async suspend.

And in order to allow the users to adjust rtc after resume,
we can clear the pm_trace_rtc_abused directly and warn users of
the broken rtc. (Without save/restore).

> drivers/base/power/trace.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/base/power/trace.c b/drivers/base/power/trace.c
> index aa9109a..1e6c611 100644
> --- a/drivers/base/power/trace.c
> +++ b/drivers/base/power/trace.c
> @@ -10,6 +10,7 @@
> #include <linux/pm-trace.h>
> #include <linux/export.h>
> #include <linux/rtc.h>
> +#include <linux/suspend.h>
>
> #include <linux/mc146818rtc.h>
>
> @@ -76,6 +77,11 @@
>
> bool pm_trace_rtc_abused __read_mostly;
> static unsigned int dev_hash_value;
> +struct rtc_time_save {
> + struct rtc_time time;
> + atomic_t saved;
> +};
>


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