Merge tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management and ACPI updates from Rafael Wysocki:
 "This includes fixes on top of the previous batch of PM+ACPI updates
  and some new material as well.

  From the new material perspective the most significant are the driver
  core changes that should allow USB devices to stay suspended over
  system suspend/resume cycles if they have been runtime-suspended
  already beforehand.  Apart from that, ACPICA is updated to upstream
  revision 20160108 (cosmetic mostly, but including one fixup on top of
  the previous ACPICA update) and there are some devfreq updates the
  didn't make it before (due to timing).

  A few recent regressions are fixed, most importantly in the cpuidle
  menu governor and in the ACPI backlight driver and some x86 platform
  drivers depending on it.

  Some more bugs are fixed and cleanups are made on top of that.

  Specifics:

   - Modify the driver core and the USB subsystem to allow USB devices
     to stay suspended over system suspend/resume cycles if they have
     been runtime-suspended already beforehand and fix some bugs on top
     of these changes (Tomeu Vizoso, Rafael Wysocki).

   - Update ACPICA to upstream revision 20160108, including updates of
     the ACPICA's copyright notices, a code fixup resulting from a
     regression fix that was necessary in the upstream code only (the
     regression fixed by it has never been present in Linux) and a
     compiler warning fix (Bob Moore, Lv Zheng).

   - Fix a recent regression in the cpuidle menu governor that broke it
     on practically all architectures other than x86 and make a couple
     of optimizations on top of that fix (Rafael Wysocki).

   - Clean up the selection of cpuidle governors depending on whether or
     not the kernel is configured for tickless systems (Jean Delvare).

   - Revert a recent commit that introduced a regression in the ACPI
     backlight driver, address the problem it attempted to fix in a
     different way and revert one more cosmetic change depending on the
     problematic commit (Hans de Goede).

   - Add two more ACPI backlight quirks (Hans de Goede).

   - Fix a few minor problems in the core devfreq code, clean it up a
     bit and update the MAINTAINERS information related to it (Chanwoo
     Choi, MyungJoo Ham).

   - Improve an error message in the ACPI fan driver (Andy Lutomirski).

   - Fix a recent build regression in the cpupower tool (Shreyas
     Prabhu)"

* tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (32 commits)
  cpuidle: menu: Avoid pointless checks in menu_select()
  sched / idle: Drop default_idle_call() fallback from call_cpuidle()
  cpupower: Fix build error in cpufreq-info
  cpuidle: Don't enable all governors by default
  cpuidle: Default to ladder governor on ticking systems
  time: nohz: Expose tick_nohz_enabled
  ACPICA: Update version to 20160108
  ACPICA: Silence a -Wbad-function-cast warning when acpi_uintptr_t is 'uintptr_t'
  ACPICA: Additional 2016 copyright changes
  ACPICA: Reduce regression fix divergence from upstream ACPICA
  ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Satellite R830
  ACPI / video: Revert "thinkpad_acpi: Use acpi_video_handles_brightness_key_presses()"
  ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit
  ACPI / video: Fix using an uninitialized mutex / list_head in acpi_video_handles_brightness_key_presses()
  ACPI / video: Revert "ACPI / video: driver must be registered before checking for keypresses"
  ACPI / fan: Improve acpi_device_update_power error message
  ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Portege R700
  cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0
  MAINTAINERS: Add devfreq-event entry
  MAINTAINERS: Add missing git repository and directory for devfreq
  ...

4 files changed, 25 insertions, 15 deletions

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 8c7930b5a65f..7e48eb5bf0a7 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -19,11 +19,9 @@ config CPU_IDLE_MULTIPLE_DRIVERS
 
 config CPU_IDLE_GOV_LADDER
 	bool "Ladder governor (for periodic timer tick)"
-	default y
 
 config CPU_IDLE_GOV_MENU
 	bool "Menu governor (for tickless system)"
-	default y
 
 config DT_IDLE_STATES
 	bool
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 17a6dc0e2111..046423b0c5ca 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -79,9 +79,9 @@ static int find_deepest_state(struct cpuidle_driver *drv,
 			      bool freeze)
 {
 	unsigned int latency_req = 0;
-	int i, ret = -ENXIO;
+	int i, ret = 0;
 
-	for (i = 0; i < drv->state_count; i++) {
+	for (i = 1; i < drv->state_count; i++) {
 		struct cpuidle_state *s = &drv->states[i];
 		struct cpuidle_state_usage *su = &dev->states_usage[i];
 
@@ -243,7 +243,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  * @drv: the cpuidle driver
  * @dev: the cpuidle device
  *
- * Returns the index of the idle state.
+ * Returns the index of the idle state.  The return value must not be negative.
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 401c0106ed34..63bd5a403e22 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -17,6 +17,7 @@
 #include <linux/pm_qos.h>
 #include <linux/module.h>
 #include <linux/jiffies.h>
+#include <linux/tick.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -184,6 +185,14 @@ static struct cpuidle_governor ladder_governor = {
  */
 static int __init init_ladder(void)
 {
+	/*
+	 * When NO_HZ is disabled, or when booting with nohz=off, the ladder
+	 * governor is better so give it a higher rating than the menu
+	 * governor.
+	 */
+	if (!tick_nohz_enabled)
+		ladder_governor.rating = 25;
+
 	return cpuidle_register_governor(&ladder_governor);
 }
 
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 7b0971d97cc3..0742b3296673 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -294,8 +294,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 		data->needs_update = 0;
 	}
 
-	data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
-
 	/* Special case when user has set very strict latency requirement */
 	if (unlikely(latency_req == 0))
 		return 0;
@@ -326,20 +324,25 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 	if (latency_req > interactivity_req)
 		latency_req = interactivity_req;
 
-	/*
-	 * We want to default to C1 (hlt), not to busy polling
-	 * unless the timer is happening really really soon.
-	 */
-	if (interactivity_req > 20 &&
-	    !drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
-		dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
+	if (CPUIDLE_DRIVER_STATE_START > 0) {
+		data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
+		/*
+		 * We want to default to C1 (hlt), not to busy polling
+		 * unless the timer is happening really really soon.
+		 */
+		if (interactivity_req > 20 &&
+		    !drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
+			dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
+			data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+	} else {
 		data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+	}
 
 	/*
 	 * Find the idle state with the lowest power while satisfying
 	 * our constraints.
 	 */
-	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+	for (i = data->last_state_idx + 1; i < drv->state_count; i++) {
 		struct cpuidle_state *s = &drv->states[i];
 		struct cpuidle_state_usage *su = &dev->states_usage[i];