Merge tag 'pm+acpi-4.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI fixes from Rafael Wysocki:
 "These fix two recent regressions (ACPICA, the generic power domains
  framework) and one crash that may happen on specific hardware
  supported since 4.1 (intel_pstate).

  Specifics:

   - Fix a regression introduced by a recent ACPICA cleanup that
     uncovered a latent bug (Lv Zheng).

   - Fix a recent regression in the generic power domains framework that
     may cause it to violate PM QoS latency constraints in some cases
     (Ulf Hansson).

   - Fix an intel_pstate driver crash on the Knights Landing chips that
     do not update the MPERF counter as often as expected by the driver
     which may result in a divide by 0 (Srinivas Pandruvada)"

* tag 'pm+acpi-4.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: intel_pstate: Fix divide by zero on Knights Landing (KNL)
  ACPICA: Tables: Fix FADT dependency regression
  PM / Domains: Fix validation of latency constraints in genpd governor

1 files changed, 6 insertions, 16 deletions

diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
index 2a4154a09e4d..85e17bacc834 100644
--- a/drivers/base/power/domain_governor.c
+++ b/drivers/base/power/domain_governor.c
@@ -77,13 +77,16 @@ static bool default_stop_ok(struct device *dev)
 				      dev_update_qos_constraint);
 
 	if (constraint_ns > 0) {
-		constraint_ns -= td->start_latency_ns;
+		constraint_ns -= td->save_state_latency_ns +
+				td->stop_latency_ns +
+				td->start_latency_ns +
+				td->restore_state_latency_ns;
 		if (constraint_ns == 0)
 			return false;
 	}
 	td->effective_constraint_ns = constraint_ns;
-	td->cached_stop_ok = constraint_ns > td->stop_latency_ns ||
-				constraint_ns == 0;
+	td->cached_stop_ok = constraint_ns >= 0;
+
 	/*
 	 * The children have been suspended already, so we don't need to take
 	 * their stop latencies into account here.
@@ -126,18 +129,6 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
 
 	off_on_time_ns = genpd->power_off_latency_ns +
 				genpd->power_on_latency_ns;
-	/*
-	 * It doesn't make sense to remove power from the domain if saving
-	 * the state of all devices in it and the power off/power on operations
-	 * take too much time.
-	 *
-	 * All devices in this domain have been stopped already at this point.
-	 */
-	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
-		if (pdd->dev->driver)
-			off_on_time_ns +=
-				to_gpd_data(pdd)->td.save_state_latency_ns;
-	}
 
 	min_off_time_ns = -1;
 	/*
@@ -193,7 +184,6 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
 		 * constraint_ns cannot be negative here, because the device has
 		 * been suspended.
 		 */
-		constraint_ns -= td->restore_state_latency_ns;
 		if (constraint_ns <= off_on_time_ns)
 			return false;