Re: S3 resume regression [1cf4f629d9d2 ("cpu/hotplug: Move online calls to hotplugged cpu")]

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Oct 27, 2016 at 08:48:57PM +0200, Thomas Gleixner wrote:
> On Thu, 27 Oct 2016, Ville Syrjälä wrote:
> > On Tue, Aug 09, 2016 at 08:20:57PM +0300, Ville Syrjälä wrote:
> > > On Thu, Jul 14, 2016 at 04:29:42PM +0800, Feng Tang wrote:
> > > > if you only want it to work, you can try an old patch
> > > > https://bugzilla.kernel.org/attachment.cgi?id=76071 from a similar bug
> > > > https://bugzilla.kernel.org/show_bug.cgi?id=41932
> > > > 
> > > > Alistair Buxton confirmed it work for 3.18 at least
> > > > https://bugzilla.kernel.org/show_bug.cgi?id=107151#c16
> > > 
> > > That patch is a bit too ripe by now. Would need a fresh squeezed one.
> > 
> > Since no one else bothered to refresh the patch I did it myself:
> > 
> > diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
> > index f6aae7977824..d73d094a8972 100644
> > --- a/kernel/time/tick-broadcast.c
> > +++ b/kernel/time/tick-broadcast.c
> > @@ -657,8 +657,16 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
> >  	 * - There are pending events on sleeping CPUs which were not
> >  	 * in the event mask
> >  	 */
> > -	if (next_event.tv64 != KTIME_MAX)
> > +	if (next_event.tv64 != KTIME_MAX) {
> > +		s64 delta = next_event.tv64 - now.tv64;
> > +
> > +		if (delta >= 10000000000) {
> > +			printk(KERN_CRIT "%s(): The delta is big: %lld\n", __func__, delta);
> > +			next_event.tv64 = now.tv64 + 3000000000;
> > +		}
> > +
> >  		tick_broadcast_set_event(dev, next_cpu, next_event);
> > +	}
> >  
> >  	raw_spin_unlock(&tick_broadcast_lock);
> > 
> > Unfortunately it doesn't do anything for me.
> 
> And I'm not surprised, because the original patch forced a 5 seconds event
> in the broadcast device on resume, aside of limiting the reprogramming.
> 
> What that old patch did, was:
> 
> 1) Make sure that the broadcast device is actually armed at resume.
> 
>    That might cause the HPET to resume proper.
> 
> 2) Force a max. 3 seconds rearm when the targeted expiry time is > than 10
>    seconds
> 
>    That might make sure that lower C-States are never entered.

Doh. I lost the other hunk somewhere. Let's try that again... And indeed
with the other hunk in tow the machine would appear to resume properly.

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index f6aae7977824..e2173aeeb00c 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -507,8 +507,12 @@ void tick_resume_broadcast(void)
 				tick_broadcast_start_periodic(bc);
 			break;
 		case TICKDEV_MODE_ONESHOT:
-			if (!cpumask_empty(tick_broadcast_mask))
+			if (!cpumask_empty(tick_broadcast_mask)) {
 				tick_resume_broadcast_oneshot(bc);
+				clockevents_program_event(bc,
+							  ktime_add_ns(ktime_get(), 5 * NSEC_PER_SEC),
+							  1);
+			}
 			break;
 		}
 	}
@@ -657,8 +661,16 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
 	 * - There are pending events on sleeping CPUs which were not
 	 * in the event mask
 	 */
-	if (next_event.tv64 != KTIME_MAX)
+	if (next_event.tv64 != KTIME_MAX) {
+		s64 delta = next_event.tv64 - now.tv64;
+
+		if (delta >= 10000000000) {
+			printk(KERN_CRIT "%s(): The delta is big: %lld\n", __func__, delta);
+			next_event.tv64 = now.tv64 + 3000000000;
+		}
+
 		tick_broadcast_set_event(dev, next_cpu, next_event);
+	}
 
 	raw_spin_unlock(&tick_broadcast_lock);

>  
> > The fortunate thing is that acpi-idle has magically been fixed in the
> > meantime, so I can at least go back to using that one and have working
> > S3.
> 
> What's the lowest C-State with acpi-idle and what's the lowest one with
> intel_idle?

acpi_idle
/sys/devices/system/cpu/cpu0/cpuidle/state3/desc:ACPI FFH INTEL MWAIT 0x30
/sys/devices/system/cpu/cpu0/cpuidle/state3/disable:0
/sys/devices/system/cpu/cpu0/cpuidle/state3/latency:100
/sys/devices/system/cpu/cpu0/cpuidle/state3/name:C3
/sys/devices/system/cpu/cpu0/cpuidle/state3/power:0
/sys/devices/system/cpu/cpu0/cpuidle/state3/residency:200
/sys/devices/system/cpu/cpu0/cpuidle/state3/time:5677316
/sys/devices/system/cpu/cpu0/cpuidle/state3/usage:5920

intel_idle:
/sys/devices/system/cpu/cpu0/cpuidle/state3/desc:MWAIT 0x30
/sys/devices/system/cpu/cpu0/cpuidle/state3/disable:0
/sys/devices/system/cpu/cpu0/cpuidle/state3/latency:100
/sys/devices/system/cpu/cpu0/cpuidle/state3/name:C4-ATM
/sys/devices/system/cpu/cpu0/cpuidle/state3/power:0
/sys/devices/system/cpu/cpu0/cpuidle/state3/residency:400
/sys/devices/system/cpu/cpu0/cpuidle/state3/time:7146705
/sys/devices/system/cpu/cpu0/cpuidle/state3/usage:6826

-- 
Ville Syrjälä
Intel OTC