3  * drivers/acpi/device_pm.c - ACPI device power management routines.
28  * acpi_power_state_string - String representation of ACPI device power state.
29  * @state: ACPI device power state to return the string representation of.
63  * acpi_device_get_power - Get power state of an ACPI device.
64  * @device: Device to get the power state of.
65  * @state: Place to store the power state of the device.
67  * This function does not update the device's power.state field, but it may
68  * update its parent's power.state field (when the parent's power state is
69  * unknown and the device's power state turns out to be D0).
71  * Also, it does not update power resource reference counters to ensure that
72  * the power state returned by it will be persistent and it may return a power
74  * (if that power state depends on any power resources).
87 			device->parent->power.state : ACPI_STATE_D0;  in acpi_device_get_power()
92 	 * Get the device's power state from power resources settings and _PSC,  in acpi_device_get_power()
95 	if (device->power.flags.power_resources) {  in acpi_device_get_power()
100 	if (device->power.flags.explicit_get) {  in acpi_device_get_power()
108 		 * The power resources settings may indicate a power state  in acpi_device_get_power()
109 		 * shallower than the actual power state of the device, because  in acpi_device_get_power()
110 		 * the same power resources may be referenced by other devices.  in acpi_device_get_power()
122 	 * If we were unsure about the device parent's power state up to this  in acpi_device_get_power()
126 	if (!device->power.flags.ignore_parent && device->parent  in acpi_device_get_power()
127 	    && device->parent->power.state == ACPI_STATE_UNKNOWN  in acpi_device_get_power()
129 		device->parent->power.state = ACPI_STATE_D0;  in acpi_device_get_power()
134 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",  in acpi_device_get_power()
142 	if (adev->power.states[state].flags.explicit_set) {  in acpi_dev_pm_explicit_set()
154  * acpi_device_set_power - Set power state of an ACPI device.
155  * @device: Device to set the power state of.
156  * @state: New power state to set.
158  * Callers must ensure that the device is power manageable before using this
170 	acpi_handle_debug(device->handle, "Power state change: %s -> %s\n",  in acpi_device_set_power()
171 			  acpi_power_state_string(device->power.state),  in acpi_device_set_power()
177 	if (state > ACPI_STATE_D0 && state == device->power.state) {  in acpi_device_set_power()
187 		 * possibly drop references to the power resources in use.  in acpi_device_set_power()
191 		if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)  in acpi_device_set_power()
193 	} else if (!device->power.states[state].flags.valid) {  in acpi_device_set_power()
194 		dev_warn(&device->dev, "Power state %s not supported\n",  in acpi_device_set_power()
199 	if (!device->power.flags.ignore_parent &&  in acpi_device_set_power()
200 	    device->parent && (state < device->parent->power.state)) {  in acpi_device_set_power()
202 			 "Cannot transition to power state %s for parent in %s\n",  in acpi_device_set_power()
204 			 acpi_power_state_string(device->parent->power.state));  in acpi_device_set_power()
209 	 * Transition Power  in acpi_device_set_power()
211 	 * In accordance with ACPI 6, _PSx is executed before manipulating power  in acpi_device_set_power()
213 	 * supposed to be executed after turning the power resources on.  in acpi_device_set_power()
217 		 * According to ACPI 6, devices cannot go from lower-power  in acpi_device_set_power()
218 		 * (deeper) states to higher-power (shallower) states.  in acpi_device_set_power()
220 		if (state < device->power.state) {  in acpi_device_set_power()
222 				 acpi_power_state_string(device->power.state),  in acpi_device_set_power()
231 		if (device->power.state < ACPI_STATE_D3_HOT) {  in acpi_device_set_power()
237 		if (device->power.flags.power_resources)  in acpi_device_set_power()
240 		int cur_state = device->power.state;  in acpi_device_set_power()
242 		if (device->power.flags.power_resources) {  in acpi_device_set_power()
252 			if (!device->power.flags.explicit_get)  in acpi_device_set_power()
256 			 * The power state of the device was set to D0 last  in acpi_device_set_power()
261 			 * and evaluate _PSC to check the device's current power  in acpi_device_set_power()
263 			 * is successful and it returns a power state different  in acpi_device_set_power()
276 		dev_warn(&device->dev, "Failed to change power state to %s\n",  in acpi_device_set_power()
279 		device->power.state = target_state;  in acpi_device_set_power()
311 	device->power.state = ACPI_STATE_UNKNOWN;  in acpi_bus_init_power()
321 	if (state < ACPI_STATE_D3_COLD && device->power.flags.power_resources) {  in acpi_bus_init_power()
322 		/* Reference count the power resources. */  in acpi_bus_init_power()
330 			 * power resources appears to be D0, it still may be  in acpi_bus_init_power()
332 			 * another device using the same power resources may  in acpi_bus_init_power()
342 		 * No power resources and missing _PSC?  Cross fingers and make  in acpi_bus_init_power()
349 	device->power.state = state;  in acpi_bus_init_power()
355  * @device: Device object whose power state is to be fixed up.
357  * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
365 	if (!device->power.flags.power_resources  in acpi_device_fix_up_power()
366 	    && !device->power.flags.explicit_get  in acpi_device_fix_up_power()
367 	    && device->power.state == ACPI_STATE_D0)  in acpi_device_fix_up_power()
379 	if (device->power.state == ACPI_STATE_UNKNOWN) {  in acpi_device_update_power()
382 			*state_p = device->power.state;  in acpi_device_update_power()
397 		if (device->power.flags.power_resources) {  in acpi_device_update_power()
400 			 * to update the power resources' reference counters.  in acpi_device_update_power()
406 		device->power.state = state;  in acpi_device_update_power()
566  * acpi_dev_pm_get_state - Get preferred power state of ACPI device.
567  * @dev: Device whose preferred target power state to return.
570  * @d_min_p: Location to store the highest power state available to the device.
571  * @d_max_p: Location to store the lowest power state available to the device.
573  * Find the lowest power (highest number) and highest power (lowest number) ACPI
574  * device power states that the device can be in while the system is in the
598 	 * If the system state is S0, the lowest power state the device can be  in acpi_dev_pm_get_state()
601 	 * lowest power state available to the device.  in acpi_dev_pm_get_state()
607 	 * If present, _SxD methods return the minimum D-state (highest power  in acpi_dev_pm_get_state()
627 		if (!adev->power.states[ret].flags.valid) {  in acpi_dev_pm_get_state()
648 	 * (ACPI 3.x), it should return the maximum (lowest power) D-state that  in acpi_dev_pm_get_state()
656 			 * must not go into any power state deeper than the  in acpi_dev_pm_get_state()
663 			if (!adev->power.states[ret].flags.valid)  in acpi_dev_pm_get_state()
682  * acpi_pm_device_sleep_state - Get preferred power state of ACPI device.
683  * @dev: Device whose preferred target power state to return.
685  * @d_max_in: Deepest low-power state to take into consideration.
686  * Return value: Preferred power state of the device on success, -ENODEV
724 			if (adev->power.states[d_max].flags.valid)  in acpi_pm_device_sleep_state()
797  * power for it.
811  * Disable the GPE associated with @adev and disable wakeup power for it.
868  * acpi_dev_pm_low_power - Put ACPI device into a low-power state.
869  * @dev: Device to put into a low-power state.
886  * acpi_dev_pm_full_power - Put ACPI device into the full-power state.
887  * @adev: ACPI device node to put into the full-power state.
896  * acpi_dev_suspend - Put device into a low-power state using ACPI.
897  * @dev: Device to put into a low-power state.
900  * Put the given device into a low-power state using the standard ACPI
903  * the power state of the device.
931  * acpi_dev_resume - Put device into the full-power state using ACPI.
932  * @dev: Device to put into the full-power state.
934  * Put the given device into the full-power state using the standard ACPI
935  * mechanism.  Set the power state of the device to ACPI D0 and disable wakeup.
956  * it into a runtime low-power state.
969  * Use ACPI to put the given device into the full-power state and carry out the
992 	if (adev->power.flags.dsw_present)  in acpi_dev_needs_resume()
999 	return state != adev->power.state;  in acpi_dev_needs_resume()
1065  * it into a low-power state during system transition into a sleep state.
1102 		dev->power.may_skip_resume = false;  in acpi_subsys_suspend_noirq()
1124  * Use ACPI to put the given device into the full-power state and carry out the
1194  * it into a low-power state during system transition into a sleep state.
1245  * acpi_dev_pm_detach - Remove ACPI power management from the device.
1247  * @power_off: Whether or not to try to remove power from the device.
1250  * notifier.  If @power_off is set, additionally remove power from the device if
1253  * Callers must ensure proper synchronization of this function with power
1268 			 * choice of the low-power state to put the device into.  in acpi_dev_pm_detach()
1279  * acpi_dev_pm_attach - Prepare device for ACPI power management.
1281  * @power_on: Whether or not to power on the device.
1288  * This assumes that the @dev's bus type uses generic power management callbacks
1289  * (or doesn't use any power management callbacks at all).
1291  * Callers must ensure proper synchronization of this function with power
1298 	 * because they require special power management handling incompatible  in acpi_dev_pm_attach()
1311 	 * Only attach the power domain to the first device if the  in acpi_dev_pm_attach()
1312 	 * companion is shared by multiple. This is to prevent doing power  in acpi_dev_pm_attach()