3  * drivers/acpi/device_pm.c - ACPI device power management routines.
27  * acpi_power_state_string - String representation of ACPI device power state.
28  * @state: ACPI device power state to return the string representation of.
62  * acpi_device_get_power - Get power state of an ACPI device.
63  * @device: Device to get the power state of.
64  * @state: Place to store the power state of the device.
66  * This function does not update the device's power.state field, but it may
67  * update its parent's power.state field (when the parent's power state is
68  * unknown and the device's power state turns out to be D0).
70  * Also, it does not update power resource reference counters to ensure that
71  * the power state returned by it will be persistent and it may return a power
73  * (if that power state depends on any power resources).
86 			device->parent->power.state : ACPI_STATE_D0;  in acpi_device_get_power()
91 	 * Get the device's power state from power resources settings and _PSC,  in acpi_device_get_power()
94 	if (device->power.flags.power_resources) {  in acpi_device_get_power()
99 	if (device->power.flags.explicit_get) {  in acpi_device_get_power()
107 		 * The power resources settings may indicate a power state  in acpi_device_get_power()
108 		 * shallower than the actual power state of the device, because  in acpi_device_get_power()
109 		 * the same power resources may be referenced by other devices.  in acpi_device_get_power()
121 	 * If we were unsure about the device parent's power state up to this  in acpi_device_get_power()
125 	if (!device->power.flags.ignore_parent && device->parent  in acpi_device_get_power()
126 	    && device->parent->power.state == ACPI_STATE_UNKNOWN  in acpi_device_get_power()
128 		device->parent->power.state = ACPI_STATE_D0;  in acpi_device_get_power()
133 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",  in acpi_device_get_power()
141 	if (adev->power.states[state].flags.explicit_set) {  in acpi_dev_pm_explicit_set()
153  * acpi_device_set_power - Set power state of an ACPI device.
154  * @device: Device to set the power state of.
155  * @state: New power state to set.
157  * Callers must ensure that the device is power manageable before using this
169 	acpi_handle_debug(device->handle, "Power state change: %s -> %s\n",  in acpi_device_set_power()
170 			  acpi_power_state_string(device->power.state),  in acpi_device_set_power()
176 	if (state > ACPI_STATE_D0 && state == device->power.state) {  in acpi_device_set_power()
186 		 * possibly drop references to the power resources in use.  in acpi_device_set_power()
190 		if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)  in acpi_device_set_power()
192 	} else if (!device->power.states[state].flags.valid) {  in acpi_device_set_power()
193 		dev_warn(&device->dev, "Power state %s not supported\n",  in acpi_device_set_power()
198 	if (!device->power.flags.ignore_parent &&  in acpi_device_set_power()
199 	    device->parent && (state < device->parent->power.state)) {  in acpi_device_set_power()
201 			 "Cannot transition to power state %s for parent in %s\n",  in acpi_device_set_power()
203 			 acpi_power_state_string(device->parent->power.state));  in acpi_device_set_power()
208 	 * Transition Power  in acpi_device_set_power()
210 	 * In accordance with ACPI 6, _PSx is executed before manipulating power  in acpi_device_set_power()
212 	 * supposed to be executed after turning the power resources on.  in acpi_device_set_power()
216 		 * According to ACPI 6, devices cannot go from lower-power  in acpi_device_set_power()
217 		 * (deeper) states to higher-power (shallower) states.  in acpi_device_set_power()
219 		if (state < device->power.state) {  in acpi_device_set_power()
221 				 acpi_power_state_string(device->power.state),  in acpi_device_set_power()
230 		if (device->power.state < ACPI_STATE_D3_HOT) {  in acpi_device_set_power()
236 		if (device->power.flags.power_resources)  in acpi_device_set_power()
239 		int cur_state = device->power.state;  in acpi_device_set_power()
241 		if (device->power.flags.power_resources) {  in acpi_device_set_power()
251 			if (!device->power.flags.explicit_get)  in acpi_device_set_power()
255 			 * The power state of the device was set to D0 last  in acpi_device_set_power()
260 			 * and evaluate _PSC to check the device's current power  in acpi_device_set_power()
262 			 * is successful and it returns a power state different  in acpi_device_set_power()
275 		dev_warn(&device->dev, "Failed to change power state to %s\n",  in acpi_device_set_power()
278 		device->power.state = target_state;  in acpi_device_set_power()
310 	device->power.state = ACPI_STATE_UNKNOWN;  in acpi_bus_init_power()
320 	if (state < ACPI_STATE_D3_COLD && device->power.flags.power_resources) {  in acpi_bus_init_power()
321 		/* Reference count the power resources. */  in acpi_bus_init_power()
329 			 * power resources appears to be D0, it still may be  in acpi_bus_init_power()
331 			 * another device using the same power resources may  in acpi_bus_init_power()
341 		 * No power resources and missing _PSC?  Cross fingers and make  in acpi_bus_init_power()
348 	device->power.state = state;  in acpi_bus_init_power()
354  * @device: Device object whose power state is to be fixed up.
356  * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
364 	if (!device->power.flags.power_resources  in acpi_device_fix_up_power()
365 	    && !device->power.flags.explicit_get  in acpi_device_fix_up_power()
366 	    && device->power.state == ACPI_STATE_D0)  in acpi_device_fix_up_power()
378 	if (device->power.state == ACPI_STATE_UNKNOWN) {  in acpi_device_update_power()
381 			*state_p = device->power.state;  in acpi_device_update_power()
396 		if (device->power.flags.power_resources) {  in acpi_device_update_power()
399 			 * to update the power resources' reference counters.  in acpi_device_update_power()
405 		device->power.state = state;  in acpi_device_update_power()
565  * acpi_dev_pm_get_state - Get preferred power state of ACPI device.
566  * @dev: Device whose preferred target power state to return.
569  * @d_min_p: Location to store the highest power state available to the device.
570  * @d_max_p: Location to store the lowest power state available to the device.
572  * Find the lowest power (highest number) and highest power (lowest number) ACPI
573  * device power states that the device can be in while the system is in the
597 	 * If the system state is S0, the lowest power state the device can be  in acpi_dev_pm_get_state()
600 	 * lowest power state available to the device.  in acpi_dev_pm_get_state()
606 	 * If present, _SxD methods return the minimum D-state (highest power  in acpi_dev_pm_get_state()
626 		if (!adev->power.states[ret].flags.valid) {  in acpi_dev_pm_get_state()
647 	 * (ACPI 3.x), it should return the maximum (lowest power) D-state that  in acpi_dev_pm_get_state()
655 			 * must not go into any power state deeper than the  in acpi_dev_pm_get_state()
662 			if (!adev->power.states[ret].flags.valid)  in acpi_dev_pm_get_state()
681  * acpi_pm_device_sleep_state - Get preferred power state of ACPI device.
682  * @dev: Device whose preferred target power state to return.
684  * @d_max_in: Deepest low-power state to take into consideration.
685  * Return value: Preferred power state of the device on success, -ENODEV
723 			if (adev->power.states[d_max].flags.valid)  in acpi_pm_device_sleep_state()
795  * power for it.
809  * Disable the GPE associated with @adev and disable wakeup power for it.
884  * acpi_dev_pm_low_power - Put ACPI device into a low-power state.
885  * @dev: Device to put into a low-power state.
902  * acpi_dev_pm_full_power - Put ACPI device into the full-power state.
903  * @adev: ACPI device node to put into the full-power state.
912  * acpi_dev_suspend - Put device into a low-power state using ACPI.
913  * @dev: Device to put into a low-power state.
916  * Put the given device into a low-power state using the standard ACPI
919  * the power state of the device.
947  * acpi_dev_resume - Put device into the full-power state using ACPI.
948  * @dev: Device to put into the full-power state.
950  * Put the given device into the full-power state using the standard ACPI
951  * mechanism.  Set the power state of the device to ACPI D0 and disable wakeup.
972  * it into a runtime low-power state.
985  * Use ACPI to put the given device into the full-power state and carry out the
1008 	if (adev->power.flags.dsw_present)  in acpi_dev_needs_resume()
1015 	return state != adev->power.state;  in acpi_dev_needs_resume()
1081  * it into a low-power state during system transition into a sleep state.
1118 		dev->power.may_skip_resume = false;  in acpi_subsys_suspend_noirq()
1140  * Use ACPI to put the given device into the full-power state and carry out the
1210  * it into a low-power state during system transition into a sleep state.
1261  * acpi_dev_pm_detach - Remove ACPI power management from the device.
1263  * @power_off: Whether or not to try to remove power from the device.
1266  * notifier.  If @power_off is set, additionally remove power from the device if
1269  * Callers must ensure proper synchronization of this function with power
1284 			 * choice of the low-power state to put the device into.  in acpi_dev_pm_detach()
1295  * acpi_dev_pm_attach - Prepare device for ACPI power management.
1297  * @power_on: Whether or not to power on the device.
1304  * This assumes that the @dev's bus type uses generic power management callbacks
1305  * (or doesn't use any power management callbacks at all).
1307  * Callers must ensure proper synchronization of this function with power
1314 	 * because they require special power management handling incompatible  in acpi_dev_pm_attach()
1329 	 * Only attach the power domain to the first device if the  in acpi_dev_pm_attach()
1330 	 * companion is shared by multiple. This is to prevent doing power  in acpi_dev_pm_attach()