Merge tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more ACPI and power management updates from Rafael Wysocki:
 "These are fixups on top of the previous PM+ACPI pull request,
  regression fixes (ACPI hotplug, cpufreq ppc-corenet), other bug fixes
  (ACPI reset, cpufreq), new PM trace points for system suspend
  profiling and a copyright notice update.

  Specifics:

   - I didn't remember correctly that the Hans de Goede's ACPI video
     patches actually didn't flip the video.use_native_backlight
     default, although we had discussed that and decided to do that.
     Since I said we would do that in the previous PM+ACPI pull request,
     make that change for real now.

   - ACPI bus check notifications for PCI host bridges don't cause the
     bus below the host bridge to be checked for changes as they should
     because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
     subsystem that forgets to add hotplug contexts to PCI host bridge
     ACPI device objects.  Create hotplug contexts for PCI host bridges
     too as appropriate.

   - Revert recent cpufreq commit related to the big.LITTLE cpufreq
     driver that breaks arm64 builds.

   - Fix for a regression in the ppc-corenet cpufreq driver introduced
     during the 3.15 cycle and causing the driver to use the remainder
     from do_div instead of the quotient.  From Ed Swarthout.

   - Resets triggered by panic activate a BUG_ON() in vmalloc.c on
     systems where the ACPI reset register is located in memory address
     space.  Fix from Randy Wright.

   - Fix for a problem with cpufreq governors that decisions made by
     them may be suboptimal due to the fact that deferrable timers are
     used by them for CPU load sampling.  From Srivatsa S Bhat.

   - Fix for a problem with the Tegra cpufreq driver where the CPU
     frequency is temporarily switched to a "stable" level that is
     different from both the initial and target frequencies during
     transitions which causes udelay() to expire earlier than it should
     sometimes.  From Viresh Kumar.

   - New trace points and rework of some existing trace points for
     system suspend/resume profiling from Todd Brandt.

   - Assorted cpufreq fixes and cleanups from Stratos Karafotis and
     Viresh Kumar.

   - Copyright notice update for suspend-and-cpuhotplug.txt from
     Srivatsa S Bhat"

* tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / hotplug / PCI: Add hotplug contexts to PCI host bridges
  PM / sleep: trace events for device PM callbacks
  cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR
  cpufreq: tegra: update comment for clarity
  cpufreq: intel_pstate: Remove duplicate CPU ID check
  cpufreq: Mark CPU0 driver with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
  PM / Documentation: Update copyright in suspend-and-cpuhotplug.txt
  cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info'
  cpufreq: governor: Be friendly towards latency-sensitive bursty workloads
  PM / sleep: trace events for suspend/resume
  cpufreq: ppc-corenet-cpu-freq: do_div use quotient
  Revert "cpufreq: Enable big.LITTLE cpufreq driver on arm64"
  cpufreq: Tegra: implement intermediate frequency callbacks
  cpufreq: add support for intermediate (stable) frequencies
  ACPI / video: Change the default for video.use_native_backlight to 1
  ACPI: Fix bug when ACPI reset register is implemented in system memory

2 files changed, 52 insertions, 18 deletions

diff --git a/drivers/pci/hotplug/acpiphp.h b/drivers/pci/hotplug/acpiphp.h
index 2b859249303..b0e61bf261a 100644
--- a/drivers/pci/hotplug/acpiphp.h
+++ b/drivers/pci/hotplug/acpiphp.h
@@ -142,6 +142,16 @@ static inline acpi_handle func_to_handle(struct acpiphp_func *func)
 	return func_to_acpi_device(func)->handle;
 }
 
+struct acpiphp_root_context {
+	struct acpi_hotplug_context hp;
+	struct acpiphp_bridge *root_bridge;
+};
+
+static inline struct acpiphp_root_context *to_acpiphp_root_context(struct acpi_hotplug_context *hp)
+{
+	return container_of(hp, struct acpiphp_root_context, hp);
+}
+
 /*
  * struct acpiphp_attention_info - device specific attention registration
  *
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 75e17833021..91aa3d78013 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -373,17 +373,13 @@ static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data,
 
 static struct acpiphp_bridge *acpiphp_dev_to_bridge(struct acpi_device *adev)
 {
-	struct acpiphp_context *context;
 	struct acpiphp_bridge *bridge = NULL;
 
 	acpi_lock_hp_context();
-	context = acpiphp_get_context(adev);
-	if (context) {
-		bridge = context->bridge;
+	if (adev->hp) {
+		bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
 		if (bridge)
 			get_bridge(bridge);
-
-		acpiphp_put_context(context);
 	}
 	acpi_unlock_hp_context();
 	return bridge;
@@ -881,7 +877,17 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
 	 */
 	get_device(&bus->dev);
 
-	if (!pci_is_root_bus(bridge->pci_bus)) {
+	acpi_lock_hp_context();
+	if (pci_is_root_bus(bridge->pci_bus)) {
+		struct acpiphp_root_context *root_context;
+
+		root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
+		if (!root_context)
+			goto err;
+
+		root_context->root_bridge = bridge;
+		acpi_set_hp_context(adev, &root_context->hp, NULL, NULL, NULL);
+	} else {
 		struct acpiphp_context *context;
 
 		/*
@@ -890,21 +896,16 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
 		 * parent is going to be handled by pciehp, in which case this
 		 * bridge is not interesting to us either.
 		 */
-		acpi_lock_hp_context();
 		context = acpiphp_get_context(adev);
-		if (!context) {
-			acpi_unlock_hp_context();
-			put_device(&bus->dev);
-			pci_dev_put(bridge->pci_dev);
-			kfree(bridge);
-			return;
-		}
+		if (!context)
+			goto err;
+
 		bridge->context = context;
 		context->bridge = bridge;
 		/* Get a reference to the parent bridge. */
 		get_bridge(context->func.parent);
-		acpi_unlock_hp_context();
 	}
+	acpi_unlock_hp_context();
 
 	/* Must be added to the list prior to calling acpiphp_add_context(). */
 	mutex_lock(&bridge_mutex);
@@ -919,6 +920,30 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
 		cleanup_bridge(bridge);
 		put_bridge(bridge);
 	}
+	return;
+
+ err:
+	acpi_unlock_hp_context();
+	put_device(&bus->dev);
+	pci_dev_put(bridge->pci_dev);
+	kfree(bridge);
+}
+
+void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
+{
+	if (pci_is_root_bus(bridge->pci_bus)) {
+		struct acpiphp_root_context *root_context;
+		struct acpi_device *adev;
+
+		acpi_lock_hp_context();
+		adev = ACPI_COMPANION(bridge->pci_bus->bridge);
+		root_context = to_acpiphp_root_context(adev->hp);
+		adev->hp = NULL;
+		acpi_unlock_hp_context();
+		kfree(root_context);
+	}
+	cleanup_bridge(bridge);
+	put_bridge(bridge);
 }
 
 /**
@@ -936,8 +961,7 @@ void acpiphp_remove_slots(struct pci_bus *bus)
 	list_for_each_entry(bridge, &bridge_list, list)
 		if (bridge->pci_bus == bus) {
 			mutex_unlock(&bridge_mutex);
-			cleanup_bridge(bridge);
-			put_bridge(bridge);
+			acpiphp_drop_bridge(bridge);
 			return;
 		}