| Message ID | 3bf82cf55c4f5ce3286f6c3fc0b2b7e4b2e5ded3.1478589736.git.yu.c.chen@intel.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
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; > +}; > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; +}; +static struct rtc_time_save rtc_saved; static int set_magic_time(unsigned int user, unsigned int file, unsigned int device) { @@ -104,6 +110,8 @@ static int set_magic_time(unsigned int user, unsigned int file, unsigned int dev n /= 24; time.tm_min = (n % 20) * 3; n /= 20; + if (!atomic_cmpxchg(&rtc_saved.saved, 0, 1)) + mc146818_get_time(&rtc_saved.time); mc146818_set_time(&time); pm_trace_rtc_abused = true; return n ? -1 : 0; @@ -240,10 +248,31 @@ int show_trace_dev_match(char *buf, size_t size) device_pm_unlock(); return ret; } +static int pm_trace_notify(struct notifier_block *nb, + unsigned long mode, void *_unused) +{ + switch (mode) { + case PM_POST_HIBERNATION: + case PM_POST_SUSPEND: + if (atomic_cmpxchg(&rtc_saved.saved, 1, 0)) { + mc146818_set_time(&rtc_saved.time); + pm_trace_rtc_abused = false; + } + break; + default: + break; + } + return 0; +} + +static struct notifier_block pm_trace_nb = { + .notifier_call = pm_trace_notify, +}; static int early_resume_init(void) { hash_value_early_read = read_magic_time(); + register_pm_notifier(&pm_trace_nb); return 0; }
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> --- drivers/base/power/trace.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)