1 files changed, 60 insertions, 40 deletions

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 735db11a9b00..88dbbb115285 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -98,17 +98,16 @@ int acpi_device_get_power(struct acpi_device *device, int *state)
 
                 /*
                  * The power resources settings may indicate a power state
-                 * shallower than the actual power state of the device.
+                 * shallower than the actual power state of the device, because
+                 * the same power resources may be referenced by other devices.
                  *
-                 * Moreover, on systems predating ACPI 4.0, if the device
-                 * doesn't depend on any power resources and _PSC returns 3,
-                 * that means "power off".  We need to maintain compatibility
-                 * with those systems.
+                 * For systems predating ACPI 4.0 we assume that D3hot is the
+                 * deepest state that can be supported.
                  */
                 if (psc > result && psc < ACPI_STATE_D3_COLD)
                         result = psc;
                 else if (result == ACPI_STATE_UNKNOWN)
-                        result = psc > ACPI_STATE_D2 ? ACPI_STATE_D3_COLD : psc;
+                        result = psc > ACPI_STATE_D2 ? ACPI_STATE_D3_HOT : psc;
         }
 
         /*
@@ -153,8 +152,8 @@ static int acpi_dev_pm_explicit_set(struct acpi_device *adev, int state)
  */
 int acpi_device_set_power(struct acpi_device *device, int state)
 {
+        int target_state = state;
         int result = 0;
-        bool cut_power = false;
 
         if (!device || !device->flags.power_manageable
             || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
@@ -169,11 +168,21 @@ int acpi_device_set_power(struct acpi_device *device, int state)
                 return 0;
         }
 
-        if (!device->power.states[state].flags.valid) {
+        if (state == ACPI_STATE_D3_COLD) {
+                /*
+                 * For transitions to D3cold we need to execute _PS3 and then
+                 * possibly drop references to the power resources in use.
+                 */
+                state = ACPI_STATE_D3_HOT;
+                /* If _PR3 is not available, use D3hot as the target state. */
+                if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)
+                        target_state = state;
+        } else if (!device->power.states[state].flags.valid) {
                 dev_warn(&device->dev, "Power state %s not supported\n",
                          acpi_power_state_string(state));
                 return -ENODEV;
         }
+
         if (!device->power.flags.ignore_parent &&
             device->parent && (state < device->parent->power.state)) {
                 dev_warn(&device->dev,
@@ -183,39 +192,38 @@ int acpi_device_set_power(struct acpi_device *device, int state)
                 return -ENODEV;
         }
 
-        /* For D3cold we should first transition into D3hot. */
-        if (state == ACPI_STATE_D3_COLD
-            && device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible) {
-                state = ACPI_STATE_D3_HOT;
-                cut_power = true;
-        }
-
-        if (state < device->power.state && state != ACPI_STATE_D0
-            && device->power.state >= ACPI_STATE_D3_HOT) {
-                dev_warn(&device->dev,
-                         "Cannot transition to non-D0 state from D3\n");
-                return -ENODEV;
-        }
-
         /*
          * Transition Power
          * ----------------
-         * In accordance with the ACPI specification first apply power (via
-         * power resources) and then evaluate _PSx.
+         * In accordance with ACPI 6, _PSx is executed before manipulating power
+         * resources, unless the target state is D0, in which case _PS0 is
+         * supposed to be executed after turning the power resources on.
          */
-        if (device->power.flags.power_resources) {
-                result = acpi_power_transition(device, state);
+        if (state > ACPI_STATE_D0) {
+                /*
+                 * According to ACPI 6, devices cannot go from lower-power
+                 * (deeper) states to higher-power (shallower) states.
+                 */
+                if (state < device->power.state) {
+                        dev_warn(&device->dev, "Cannot transition from %s to %s\n",
+                                 acpi_power_state_string(device->power.state),
+                                 acpi_power_state_string(state));
+                        return -ENODEV;
+                }
+
+                result = acpi_dev_pm_explicit_set(device, state);
                 if (result)
                         goto end;
-        }
-        result = acpi_dev_pm_explicit_set(device, state);
-        if (result)
-                goto end;
 
-        if (cut_power) {
-                device->power.state = state;
-                state = ACPI_STATE_D3_COLD;
-                result = acpi_power_transition(device, state);
+                if (device->power.flags.power_resources)
+                        result = acpi_power_transition(device, target_state);
+        } else {
+                if (device->power.flags.power_resources) {
+                        result = acpi_power_transition(device, ACPI_STATE_D0);
+                        if (result)
+                                goto end;
+                }
+                result = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
         }
 
  end:
@@ -223,7 +231,7 @@ int acpi_device_set_power(struct acpi_device *device, int state)
                 dev_warn(&device->dev, "Failed to change power state to %s\n",
                          acpi_power_state_string(state));
         } else {
-                device->power.state = state;
+                device->power.state = target_state;
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                   "Device [%s] transitioned to %s\n",
                                   device->pnp.bus_id,
@@ -264,13 +272,24 @@ int acpi_bus_init_power(struct acpi_device *device)
                 return result;
 
         if (state < ACPI_STATE_D3_COLD && device->power.flags.power_resources) {
+                /* Reference count the power resources. */
                 result = acpi_power_on_resources(device, state);
                 if (result)
                         return result;
 
-                result = acpi_dev_pm_explicit_set(device, state);
-                if (result)
-                        return result;
+                if (state == ACPI_STATE_D0) {
+                        /*
+                         * If _PSC is not present and the state inferred from
+                         * power resources appears to be D0, it still may be
+                         * necessary to execute _PS0 at this point, because
+                         * another device using the same power resources may
+                         * have been put into D0 previously and that's why we
+                         * see D0 here.
+                         */
+                        result = acpi_dev_pm_explicit_set(device, state);
+                        if (result)
+                                return result;
+                }
         } else if (state == ACPI_STATE_UNKNOWN) {
                 /*
                  * No power resources and missing _PSC?  Cross fingers and make
@@ -603,12 +622,12 @@ int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p, int d_max_in)
         if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)
                 return -EINVAL;
 
-        if (d_max_in > ACPI_STATE_D3_HOT) {
+        if (d_max_in > ACPI_STATE_D2) {
                 enum pm_qos_flags_status stat;
 
                 stat = dev_pm_qos_flags(dev, PM_QOS_FLAG_NO_POWER_OFF);
                 if (stat == PM_QOS_FLAGS_ALL)
-                        d_max_in = ACPI_STATE_D3_HOT;
+                        d_max_in = ACPI_STATE_D2;
         }
 
         adev = ACPI_COMPANION(dev);
@@ -953,6 +972,7 @@ EXPORT_SYMBOL_GPL(acpi_subsys_prepare);
  */
 void acpi_subsys_complete(struct device *dev)
 {
+        pm_generic_complete(dev);
         /*
          * If the device had been runtime-suspended before the system went into
          * the sleep state it is going out of and it has never been resumed till