Merge tag 'acpi-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI updates from Rafael Wysocki:
"These rework the handling of ACPI device objects to use the driver
core facilities for managing child ones instead of some questionable
home-grown ways without the requisite locking and reference counting,
clean up the EC driver, improve suspend-to-idle handling on x86, add
some systems to the ACPI backlight quirk list, fix some assorted
issues, clean up code and improve documentation.

Specifics:

- Use facilities provided by the driver core and some additional
helpers to handle the children of a given ACPI device object in
multiple places instead of using the children and node list heads
in struct acpi_device which is error prone (Rafael Wysocki).

- Fix ACPI-related device reference counting issue in the hisi_lpc
bus driver (Yang Yingliang).

- Drop the children and node list heads that are not needed any more
from struct acpi_device (Rafael Wysocki).

- Drop driver member from struct acpi_device (Uwe Kleine-König).

- Drop redundant check from acpi_device_remove() (Uwe Kleine-König).

- Prepare the CPPC library for handling backwards-compatible future
_CPC return package formats gracefully (Rafael Wysocki).

- Clean up the ACPI EC driver after previous changes in it (Hans de
Goede).

- Drop leftover acpi_processor_get_limit_info() declaration (Riwen
Lu).

- Split out thermal initialization from ACPI PSS (Riwen Lu).

- Annotate more functions in the ACPI CPU idle driver to live in the
cpuidle section (Guilherme G. Piccoli).

- Fix _EINJ vs "special purpose" EFI memory regions (Dan Williams).

- Implement a better fix to avoid spamming the console with old error
logs (Tony Luck).

- Fix typo in a comment in the APEI code (Xiang wangx).

- Save NVS memory during transitions into S3 on Lenovo G40-45 (Manyi
Li).

- Add support for upcoming AMD uPEP device ID AMDI008 to the ACPI
suspend-to-idle driver for x86 platforms (Shyam Sundar S K).

- Clean up checks related to the ACPI_FADT_LOW_POWER_S0 platform flag
in the LPIT table driver and the suspend-to-idle driver for x86
platforms (Rafael Wysocki).

- Print information messages regarding declared LPS0 idle support in
the platform firmware (Rafael Wysocki).

- Fix missing check in register_device_clock() in the ACPI driver for
Intel SoCs (huhai).

- Fix ACS setup in the VIOT table parser (Eric Auger).

- Skip IRQ override on AMD Zen platforms where it's harmful
(Chuanhong Guo).

- Use native backlight on Dell Inspiron N4010 (Hans de Goede).

- Use native backlight on some TongFang devices (Werner Sembach).

- Drop X86 dependency from the ACPI backlight driver Kconfig (Riwen
Lu).

- Shorten the quirk list in the ACPI backlight driver by identifying
Clevo by board_name only (Werner Sembach).

- Remove useless NULL pointer checks from 2 ACPI PCI link management
functions (Andrey Strachuk).

- Fix obsolete example in the ACPI EINJ documentation (Qifu Zhang).

- Update links and references to _DSD-related documents (Sudeep
Holla)"

* tag 'acpi-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (46 commits)
ACPI/PCI: Remove useless NULL pointer checks
ACPI: CPPC: Do not prevent CPPC from working in the future
ACPI: PM: x86: Print messages regarding LPS0 idle support
ACPI: resource: skip IRQ override on AMD Zen platforms
Documentation: ACPI: EINJ: Fix obsolete example
ACPI: video: Use native backlight on Dell Inspiron N4010
ACPI: PM: s2idle: Use LPS0 idle if ACPI_FADT_LOW_POWER_S0 is unset
Revert "ACPI / PM: LPIT: Register sysfs attributes based on FADT"
ACPI: video: Shortening quirk list by identifying Clevo by board_name only
ACPI: video: Force backlight native for some TongFang devices
ACPI: PM: s2idle: Add support for upcoming AMD uPEP HID AMDI008
ACPI: VIOT: Fix ACS setup
ACPI: bus: Drop unused list heads from struct acpi_device
hisi_lpc: Use acpi_dev_for_each_child()
bus: hisi_lpc: fix missing platform_device_put() in hisi_lpc_acpi_probe()
ACPI: bus: Drop driver member of struct acpi_device
ACPI: bus: Drop redundant check in acpi_device_remove()
ACPI: APEI: Fix _EINJ vs EFI_MEMORY_SP
ACPI: LPSS: Fix missing check in register_device_clock()
ACPI: APEI: Better fix to avoid spamming the console with old error logs
...

Documentation/firmware-guide/acpi/DSD-properties-rules.rst

···
 
 In the ACPI _DSD context it is an element of the sub-package following the
 generic Device Properties UUID in the _DSD return package as specified in the
-Device Properties UUID definition document [1]_.
+section titled "Well-Known _DSD UUIDs and Data Structure Formats" sub-section
+"Device Properties UUID" in _DSD (Device Specific Data) Implementation Guide
+document [1]_.
 
 It also may be regarded as the definition of a key and the associated data type
 that can be returned by _DSD in the Device Properties UUID sub-package for a
···
 associated with an additional key (name) allowing the subset to be referred
 to as a whole (and to be treated as a separate entity).  The canonical
 representation of property subsets is via the mechanism specified in the
-Hierarchical Properties Extension UUID definition document [2]_.
+section titled "Well-Known _DSD UUIDs and Data Structure Formats" sub-section
+"Hierarchical Data Extension UUID" in _DSD (Device Specific Data)
+Implementation Guide document [1]_.
 
 Property sets may be hierarchical.  That is, a property set may contain
 multiple property subsets that each may contain property subsets of its
···
 References
 ==========
 
-.. [1] https://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf
-.. [2] https://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf
+.. [1] https://github.com/UEFI/DSD-Guide

Documentation/firmware-guide/acpi/apei/einj.rst

···
   0x00000008	Memory Correctable
   0x00000010	Memory Uncorrectable non-fatal
   # echo 0x12345000 > param1		# Set memory address for injection
-  # echo $((-1 << 12)) > param2		# Mask 0xfffffffffffff000 - anywhere in this page
+  # echo 0xfffffffffffff000 > param2		# Mask - anywhere in this page
   # echo 0x8 > error_type			# Choose correctable memory error
   # echo 1 > error_inject			# Inject now
 

drivers/acpi/Kconfig

···
 
 config ACPI_VIDEO
 	tristate "Video"
-	depends on X86 && BACKLIGHT_CLASS_DEVICE
+	depends on BACKLIGHT_CLASS_DEVICE
 	depends on INPUT
 	select THERMAL
 	help
···
 
 config ACPI_CPU_FREQ_PSS
 	bool
-	select THERMAL
 
 config ACPI_PROCESSOR_CSTATE
 	def_bool y
···
 	depends on X86 || IA64 || ARM64 || LOONGARCH
 	select ACPI_PROCESSOR_IDLE
 	select ACPI_CPU_FREQ_PSS if X86 || IA64 || LOONGARCH
+	select THERMAL
 	default y
 	help
 	  This driver adds support for the ACPI Processor package. It is required

drivers/acpi/Makefile

···
 obj-$(CONFIG_ACPI_PFRUT)	+= pfr_update.o pfr_telemetry.o
 
 # processor has its own "processor." module_param namespace
-processor-y			:= processor_driver.o
+processor-y			:= processor_driver.o processor_thermal.o
 processor-$(CONFIG_ACPI_PROCESSOR_IDLE) += processor_idle.o
-processor-$(CONFIG_ACPI_CPU_FREQ_PSS)	+= processor_throttling.o	\
-	processor_thermal.o
+processor-$(CONFIG_ACPI_CPU_FREQ_PSS)	+= processor_throttling.o
 processor-$(CONFIG_CPU_FREQ)	+= processor_perflib.o
 
 obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o

drivers/acpi/acpi_lpit.c

···
 		if (!info->iomem_addr)
 			return;
 
-		if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
-			return;
-
 		/* Silently fail, if cpuidle attribute group is not present */
 		sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
 					&dev_attr_low_power_idle_system_residency_us.attr,
 					"cpuidle");
 	} else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
-		if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
-			return;
-
 		/* Silently fail, if cpuidle attribute group is not present */
 		sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
 					&dev_attr_low_power_idle_cpu_residency_us.attr,

drivers/acpi/acpi_lpss.c

···
 	if (!lpss_clk_dev)
 		lpt_register_clock_device();
 
+	if (IS_ERR(lpss_clk_dev))
+		return PTR_ERR(lpss_clk_dev);
+
 	clk_data = platform_get_drvdata(lpss_clk_dev);
 	if (!clk_data)
 		return -ENODEV;

drivers/acpi/acpi_video.c

···
 	return 0;
 }
 
-static int
-acpi_video_bus_get_one_device(struct acpi_device *device,
-			      struct acpi_video_bus *video)
+static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
 {
-	unsigned long long device_id;
-	int status, device_type;
-	struct acpi_video_device *data;
+	struct acpi_video_bus *video = arg;
 	struct acpi_video_device_attrib *attribute;
+	struct acpi_video_device *data;
+	unsigned long long device_id;
+	acpi_status status;
+	int device_type;
 
-	status =
-	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
-	/* Some device omits _ADR, we skip them instead of fail */
+	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
+	/* Skip devices without _ADR instead of failing. */
 	if (ACPI_FAILURE(status))
-		return 0;
+		goto exit;
 
 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
-	if (!data)
+	if (!data) {
+		dev_dbg(&device->dev, "Cannot attach\n");
 		return -ENOMEM;
+	}
 
 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
···
 	list_add_tail(&data->entry, &video->video_device_list);
 	mutex_unlock(&video->device_list_lock);
 
-	return status;
+exit:
+	video->child_count++;
+	return 0;
 }
 
 /*
···
 acpi_video_bus_get_devices(struct acpi_video_bus *video,
 			   struct acpi_device *device)
 {
-	int status = 0;
-	struct acpi_device *dev;
-
 	/*
 	 * There are systems where video module known to work fine regardless
 	 * of broken _DOD and ignoring returned value here doesn't cause
···
 	 */
 	acpi_video_device_enumerate(video);
 
-	list_for_each_entry(dev, &device->children, node) {
-
-		status = acpi_video_bus_get_one_device(dev, video);
-		if (status) {
-			dev_err(&dev->dev, "Can't attach device\n");
-			break;
-		}
-		video->child_count++;
-	}
-	return status;
+	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
 }
 
 /* acpi_video interface */

drivers/acpi/apei/apei-base.c

···
  * apei-base.c - ACPI Platform Error Interface (APEI) supporting
  * infrastructure
  *
- * APEI allows to report errors (for example from the chipset) to the
+ * APEI allows to report errors (for example from the chipset) to
  * the operating system. This improves NMI handling especially. In
  * addition it supports error serialization and error injection.
  *

drivers/acpi/apei/bert.c

···
 
 #undef pr_fmt
 #define pr_fmt(fmt) "BERT: " fmt
+
+#define ACPI_BERT_PRINT_MAX_RECORDS 5
 #define ACPI_BERT_PRINT_MAX_LEN 1024
 
 static int bert_disable;
 
+/*
+ * Print "all" the error records in the BERT table, but avoid huge spam to
+ * the console if the BIOS included oversize records, or too many records.
+ * Skipping some records here does not lose anything because the full
+ * data is available to user tools in:
+ *	/sys/firmware/acpi/tables/data/BERT
+ */
 static void __init bert_print_all(struct acpi_bert_region *region,
 				  unsigned int region_len)
 {
 	struct acpi_hest_generic_status *estatus =
 		(struct acpi_hest_generic_status *)region;
 	int remain = region_len;
+	int printed = 0, skipped = 0;
 	u32 estatus_len;
 
 	while (remain >= sizeof(struct acpi_bert_region)) {
···
 		if (remain < estatus_len) {
 			pr_err(FW_BUG "Truncated status block (length: %u).\n",
 			       estatus_len);
-			return;
+			break;
 		}
 
 		/* No more error records. */
 		if (!estatus->block_status)
-			return;
+			break;
 
 		if (cper_estatus_check(estatus)) {
 			pr_err(FW_BUG "Invalid error record.\n");
-			return;
+			break;
 		}
 
-		pr_info_once("Error records from previous boot:\n");
-		if (region_len < ACPI_BERT_PRINT_MAX_LEN)
+		if (estatus_len < ACPI_BERT_PRINT_MAX_LEN &&
+		    printed < ACPI_BERT_PRINT_MAX_RECORDS) {
+			pr_info_once("Error records from previous boot:\n");
 			cper_estatus_print(KERN_INFO HW_ERR, estatus);
-		else
-			pr_info_once("Max print length exceeded, table data is available at:\n"
-				     "/sys/firmware/acpi/tables/data/BERT");
+			printed++;
+		} else {
+			skipped++;
+		}
 
 		/*
 		 * Because the boot error source is "one-time polled" type,
···
 		estatus = (void *)estatus + estatus_len;
 		remain -= estatus_len;
 	}
+
+	if (skipped)
+		pr_info(HW_ERR "Skipped %d error records\n", skipped);
 }
 
 static int __init setup_bert_disable(char *str)

drivers/acpi/apei/einj.c

···
 				!= REGION_INTERSECTS) &&
 	     (region_intersects(base_addr, size, IORESOURCE_MEM, IORES_DESC_PERSISTENT_MEMORY)
 				!= REGION_INTERSECTS) &&
+	     (region_intersects(base_addr, size, IORESOURCE_MEM, IORES_DESC_SOFT_RESERVED)
+				!= REGION_INTERSECTS) &&
 	     !arch_is_platform_page(base_addr)))
 		return -EINVAL;
 

drivers/acpi/bus.c

···
 static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
 {
 	struct acpi_device *adev;
-	struct acpi_driver *driver;
 	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
 	bool hotplug_event = false;
 
···
 	if (!adev)
 		goto err;
 
-	driver = adev->driver;
-	if (driver && driver->ops.notify &&
-	    (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
-		driver->ops.notify(adev, type);
+	if (adev->dev.driver) {
+		struct acpi_driver *driver = to_acpi_driver(adev->dev.driver);
+
+		if (driver && driver->ops.notify &&
+		    (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
+			driver->ops.notify(adev, type);
+	}
 
 	if (!hotplug_event) {
 		acpi_bus_put_acpi_device(adev);
···
 static void acpi_notify_device(acpi_handle handle, u32 event, void *data)
 {
 	struct acpi_device *device = data;
+	struct acpi_driver *acpi_drv = to_acpi_driver(device->dev.driver);
 
-	device->driver->ops.notify(device, event);
+	acpi_drv->ops.notify(device, event);
 }
 
 static void acpi_notify_device_fixed(void *data)
···
 	if (ret)
 		return ret;
 
-	acpi_dev->driver = acpi_drv;
-
 	pr_debug("Driver [%s] successfully bound to device [%s]\n",
 		 acpi_drv->name, acpi_dev->pnp.bus_id);
 
···
 			if (acpi_drv->ops.remove)
 				acpi_drv->ops.remove(acpi_dev);
 
-			acpi_dev->driver = NULL;
 			acpi_dev->driver_data = NULL;
 			return ret;
 		}
···
 static void acpi_device_remove(struct device *dev)
 {
 	struct acpi_device *acpi_dev = to_acpi_device(dev);
-	struct acpi_driver *acpi_drv = acpi_dev->driver;
+	struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
 
-	if (acpi_drv) {
-		if (acpi_drv->ops.notify)
-			acpi_device_remove_notify_handler(acpi_dev);
-		if (acpi_drv->ops.remove)
-			acpi_drv->ops.remove(acpi_dev);
-	}
-	acpi_dev->driver = NULL;
+	if (acpi_drv->ops.notify)
+		acpi_device_remove_notify_handler(acpi_dev);
+
+	if (acpi_drv->ops.remove)
+		acpi_drv->ops.remove(acpi_dev);
+
 	acpi_dev->driver_data = NULL;
 
 	put_device(dev);
···
 
 	return adwc->fn(to_acpi_device(dev), adwc->data);
 }
+EXPORT_SYMBOL_GPL(acpi_dev_for_each_child);
 
 int acpi_dev_for_each_child(struct acpi_device *adev,
 			    int (*fn)(struct acpi_device *, void *), void *data)
···
 	};
 
 	return device_for_each_child(&adev->dev, &adwc, acpi_dev_for_one_check);
+}
+
+int acpi_dev_for_each_child_reverse(struct acpi_device *adev,
+				    int (*fn)(struct acpi_device *, void *),
+				    void *data)
+{
+	struct acpi_dev_walk_context adwc = {
+		.fn = fn,
+		.data = data,
+	};
+
+	return device_for_each_child_reverse(&adev->dev, &adwc, acpi_dev_for_one_check);
 }
 
 /* --------------------------------------------------------------------------
···
 
 	pci_mmcfg_late_init();
 	acpi_iort_init();
+	acpi_viot_early_init();
 	acpi_hest_init();
 	acpi_ghes_init();
 	acpi_scan_init();

drivers/acpi/container.c

···
 
 #ifdef CONFIG_ACPI_CONTAINER
 
+static int check_offline(struct acpi_device *adev, void *not_used)
+{
+	if (acpi_scan_is_offline(adev, false))
+		return 0;
+
+	return -EBUSY;
+}
+
 static int acpi_container_offline(struct container_dev *cdev)
 {
-	struct acpi_device *adev = ACPI_COMPANION(&cdev->dev);
-	struct acpi_device *child;
-
 	/* Check all of the dependent devices' physical companions. */
-	list_for_each_entry(child, &adev->children, node)
-		if (!acpi_scan_is_offline(child, false))
-			return -EBUSY;
-
-	return 0;
+	return acpi_dev_for_each_child(ACPI_COMPANION(&cdev->dev), check_offline, NULL);
 }
 
 static void acpi_container_release(struct device *dev)

drivers/acpi/cppc_acpi.c

···
 	return 0;
 }
 
-/* Check if CPPC revision + num_ent combination is supported */
-static bool is_cppc_supported(int revision, int num_ent)
-{
-	int expected_num_ent;
-
-	switch (revision) {
-	case CPPC_V2_REV:
-		expected_num_ent = CPPC_V2_NUM_ENT;
-		break;
-	case CPPC_V3_REV:
-		expected_num_ent = CPPC_V3_NUM_ENT;
-		break;
-	default:
-		pr_debug("Firmware exports unsupported CPPC revision: %d\n",
-			revision);
-		return false;
-	}
-
-	if (expected_num_ent != num_ent) {
-		pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
-			num_ent, expected_num_ent, revision);
-		return false;
-	}
-
-	return true;
-}
-
 /*
  * An example CPC table looks like the following.
  *
···
 			 cpc_obj->type, pr->id);
 		goto out_free;
 	}
-	cpc_ptr->num_entries = num_ent;
 
 	/* Second entry should be revision. */
 	cpc_obj = &out_obj->package.elements[1];
···
 			 cpc_obj->type, pr->id);
 		goto out_free;
 	}
-	cpc_ptr->version = cpc_rev;
 
-	if (!is_cppc_supported(cpc_rev, num_ent))
+	if (cpc_rev < CPPC_V2_REV) {
+		pr_debug("Unsupported _CPC Revision (%d) for CPU:%d\n", cpc_rev,
+			 pr->id);
 		goto out_free;
+	}
+
+	/*
+	 * Disregard _CPC if the number of entries in the return pachage is not
+	 * as expected, but support future revisions being proper supersets of
+	 * the v3 and only causing more entries to be returned by _CPC.
+	 */
+	if ((cpc_rev == CPPC_V2_REV && num_ent != CPPC_V2_NUM_ENT) ||
+	    (cpc_rev == CPPC_V3_REV && num_ent != CPPC_V3_NUM_ENT) ||
+	    (cpc_rev > CPPC_V3_REV && num_ent <= CPPC_V3_NUM_ENT)) {
+		pr_debug("Unexpected number of _CPC return package entries (%d) for CPU:%d\n",
+			 num_ent, pr->id);
+		goto out_free;
+	}
+	if (cpc_rev > CPPC_V3_REV) {
+		num_ent = CPPC_V3_NUM_ENT;
+		cpc_rev = CPPC_V3_REV;
+	}
+
+	cpc_ptr->num_entries = num_ent;
+	cpc_ptr->version = cpc_rev;
 
 	/* Iterate through remaining entries in _CPC */
 	for (i = 2; i < num_ent; i++) {

drivers/acpi/device_pm.c

···
 }
 EXPORT_SYMBOL_GPL(acpi_device_fix_up_power);
 
+static int fix_up_power_if_applicable(struct acpi_device *adev, void *not_used)
+{
+	if (adev->status.present && adev->status.enabled)
+		acpi_device_fix_up_power(adev);
+
+	return 0;
+}
+
+/**
+ * acpi_device_fix_up_power_extended - Force device and its children into D0.
+ * @adev: Parent device object whose power state is to be fixed up.
+ *
+ * Call acpi_device_fix_up_power() for @adev and its children so long as they
+ * are reported as present and enabled.
+ */
+void acpi_device_fix_up_power_extended(struct acpi_device *adev)
+{
+	acpi_device_fix_up_power(adev);
+	acpi_dev_for_each_child(adev, fix_up_power_if_applicable, NULL);
+}
+EXPORT_SYMBOL_GPL(acpi_device_fix_up_power_extended);
+
 int acpi_device_update_power(struct acpi_device *device, int *state_p)
 {
 	int state;

drivers/acpi/device_sysfs.c

···
 		return -EINVAL;
 
 	if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
-	    && !acpi_device->driver)
+	    && !d->driver)
 		return -ENODEV;
 
 	status = acpi_get_type(acpi_device->handle, &not_used);

drivers/acpi/ec.c

···
 static struct workqueue_struct *ec_query_wq;
 
 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
-static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 
···
 	if (ec->data_addr == 0 || ec->command_addr == 0)
 		return AE_OK;
 
-	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
-		/*
-		 * Always inherit the GPE number setting from the ECDT
-		 * EC.
-		 */
-		ec->gpe = boot_ec->gpe;
-	} else {
-		/* Get GPE bit assignment (EC events). */
-		/* TODO: Add support for _GPE returning a package */
-		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
-		if (ACPI_SUCCESS(status))
-			ec->gpe = tmp;
+	/* Get GPE bit assignment (EC events). */
+	/* TODO: Add support for _GPE returning a package */
+	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
+	if (ACPI_SUCCESS(status))
+		ec->gpe = tmp;
+	/*
+	 * Errors are non-fatal, allowing for ACPI Reduced Hardware
+	 * platforms which use GpioInt instead of GPE.
+	 */
 
-		/*
-		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
-		 * platforms which use GpioInt instead of GPE.
-		 */
-	}
 	/* Use the global lock for all EC transactions? */
 	tmp = 0;
 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
···
 		}
 
 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
-		    ec->data_addr == boot_ec->data_addr &&
-		    !EC_FLAGS_TRUST_DSDT_GPE) {
+		    ec->data_addr == boot_ec->data_addr) {
 			/*
-			 * Trust PNP0C09 namespace location rather than
-			 * ECDT ID. But trust ECDT GPE rather than _GPE
-			 * because of ASUS quirks, so do not change
-			 * boot_ec->gpe to ec->gpe.
+			 * Trust PNP0C09 namespace location rather than ECDT ID.
+			 * But trust ECDT GPE rather than _GPE because of ASUS
+			 * quirks. So do not change boot_ec->gpe to ec->gpe,
+			 * except when the TRUST_DSDT_GPE quirk is set.
 			 */
 			boot_ec->handle = ec->handle;
+
+			if (EC_FLAGS_TRUST_DSDT_GPE)
+				boot_ec->gpe = ec->gpe;
+
 			acpi_handle_debug(ec->handle, "duplicated.\n");
 			acpi_ec_free(ec);
 			ec = boot_ec;
···
 	return 0;
 }
 
-/*
- * Some DSDTs contain wrong GPE setting.
- * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
- * https://bugzilla.kernel.org/show_bug.cgi?id=195651
- */
-static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
-{
-	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
-	EC_FLAGS_IGNORE_DSDT_GPE = 1;
-	return 0;
-}
-
 static const struct dmi_system_id ec_dmi_table[] __initconst = {
 	{
-	ec_correct_ecdt, "MSI MS-171F", {
-	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
-	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
+		/*
+		 * MSI MS-171F
+		 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
+		 */
+		.callback = ec_correct_ecdt,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
+		},
+	},
 	{
-	ec_honor_ecdt_gpe, "ASUS FX502VD", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
+		/*
+		 * HP Pavilion Gaming Laptop 15-cx0xxx
+		 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
+		 */
+		.callback = ec_honor_dsdt_gpe,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
+		},
+	},
 	{
-	ec_honor_ecdt_gpe, "ASUS FX502VE", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BA", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X505BA"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BP", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X505BP"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BA", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X542BA"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BP", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X542BP"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUS X550VXK", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
-	{
-	ec_honor_ecdt_gpe, "ASUS X580VD", {
-	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
-	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
-	{
-	/* https://bugzilla.kernel.org/show_bug.cgi?id=209989 */
-	ec_honor_dsdt_gpe, "HP Pavilion Gaming Laptop 15-cx0xxx", {
-	DMI_MATCH(DMI_SYS_VENDOR, "HP"),
-	DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),}, NULL},
-	{
-	ec_clear_on_resume, "Samsung hardware", {
-	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
-	{},
+		/*
+		 * Samsung hardware
+		 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
+		 */
+		.callback = ec_clear_on_resume,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+		},
+	},
+	{}
 };
 
 void __init acpi_ec_ecdt_probe(void)
···
 
 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
 	{
-		.ident = "Thinkpad X1 Carbon 6th",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
 		},
 	},
 	{
-		.ident = "ThinkPad X1 Carbon 6th",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
-		},
-	},
-	{
-		.ident = "ThinkPad X1 Yoga 3rd",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
 		},
 	},
 	{
-		.ident = "HP ZHAN 66 Pro",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
 			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),

drivers/acpi/glue.c

···
 #define FIND_CHILD_MIN_SCORE	1
 #define FIND_CHILD_MAX_SCORE	2
 
+static int match_any(struct acpi_device *adev, void *not_used)
+{
+	return 1;
+}
+
+static bool acpi_dev_has_children(struct acpi_device *adev)
+{
+	return acpi_dev_for_each_child(adev, match_any, NULL) > 0;
+}
+
 static int find_child_checks(struct acpi_device *adev, bool check_children)
 {
 	unsigned long long sta;
 	acpi_status status;
 
-	if (check_children && list_empty(&adev->children))
+	if (check_children && !acpi_dev_has_children(adev))
 		return -ENODEV;
 
 	status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
···
 	return FIND_CHILD_MAX_SCORE;
 }
 
+struct find_child_walk_data {
+	struct acpi_device *adev;
+	u64 address;
+	int score;
+	bool check_sta;
+	bool check_children;
+};
+
+static int check_one_child(struct acpi_device *adev, void *data)
+{
+	struct find_child_walk_data *wd = data;
+	int score;
+
+	if (!adev->pnp.type.bus_address || acpi_device_adr(adev) != wd->address)
+		return 0;
+
+	if (!wd->adev) {
+		/*
+		 * This is the first matching object, so save it.  If it is not
+		 * necessary to look for any other matching objects, stop the
+		 * search.
+		 */
+		wd->adev = adev;
+		return !(wd->check_sta || wd->check_children);
+	}
+
+	/*
+	 * There is more than one matching device object with the same _ADR
+	 * value.  That really is unexpected, so we are kind of beyond the scope
+	 * of the spec here.  We have to choose which one to return, though.
+	 *
+	 * First, get the score for the previously found object and terminate
+	 * the walk if it is maximum.
+	*/
+	if (!wd->score) {
+		score = find_child_checks(wd->adev, wd->check_children);
+		if (score == FIND_CHILD_MAX_SCORE)
+			return 1;
+
+		wd->score = score;
+	}
+	/*
+	 * Second, if the object that has just been found has a better score,
+	 * replace the previously found one with it and terminate the walk if
+	 * the new score is maximum.
+	 */
+	score = find_child_checks(adev, wd->check_children);
+	if (score > wd->score) {
+		wd->adev = adev;
+		if (score == FIND_CHILD_MAX_SCORE)
+			return 1;
+
+		wd->score = score;
+	}
+
+	/* Continue, because there may be better matches. */
+	return 0;
+}
+
+static struct acpi_device *acpi_find_child(struct acpi_device *parent,
+					   u64 address, bool check_children,
+					   bool check_sta)
+{
+	struct find_child_walk_data wd = {
+		.address = address,
+		.check_children = check_children,
+		.check_sta = check_sta,
+		.adev = NULL,
+		.score = 0,
+	};
+
+	if (parent)
+		acpi_dev_for_each_child(parent, check_one_child, &wd);
+
+	return wd.adev;
+}
+
 struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
 					   u64 address, bool check_children)
 {
-	struct acpi_device *adev, *ret = NULL;
-	int ret_score = 0;
-
-	if (!parent)
-		return NULL;
-
-	list_for_each_entry(adev, &parent->children, node) {
-		acpi_bus_address addr = acpi_device_adr(adev);
-		int score;
-
-		if (!adev->pnp.type.bus_address || addr != address)
-			continue;
-
-		if (!ret) {
-			/* This is the first matching object.  Save it. */
-			ret = adev;
-			continue;
-		}
-		/*
-		 * There is more than one matching device object with the same
-		 * _ADR value.  That really is unexpected, so we are kind of
-		 * beyond the scope of the spec here.  We have to choose which
-		 * one to return, though.
-		 *
-		 * First, check if the previously found object is good enough
-		 * and return it if so.  Second, do the same for the object that
-		 * we've just found.
-		 */
-		if (!ret_score) {
-			ret_score = find_child_checks(ret, check_children);
-			if (ret_score == FIND_CHILD_MAX_SCORE)
-				return ret;
-		}
-		score = find_child_checks(adev, check_children);
-		if (score == FIND_CHILD_MAX_SCORE) {
-			return adev;
-		} else if (score > ret_score) {
-			ret = adev;
-			ret_score = score;
-		}
-	}
-	return ret;
+	return acpi_find_child(parent, address, check_children, true);
 }
 EXPORT_SYMBOL_GPL(acpi_find_child_device);
+
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr)
+{
+	return acpi_find_child(adev, adr, false, false);
+}
+EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);
 
 static void acpi_physnode_link_name(char *buf, unsigned int node_id)
 {

drivers/acpi/pci_link.c

···
 	case ACPI_RESOURCE_TYPE_IRQ:
 		{
 			struct acpi_resource_irq *p = &resource->data.irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				acpi_handle_debug(handle,
 						  "Blank _PRS IRQ resource\n");
 				return AE_OK;
···
 		{
 			struct acpi_resource_extended_irq *p =
 			    &resource->data.extended_irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				acpi_handle_debug(handle,
 						  "Blank _PRS EXT IRQ resource\n");
 				return AE_OK;
···
 	case ACPI_RESOURCE_TYPE_IRQ:
 		{
 			struct acpi_resource_irq *p = &resource->data.irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				/*
 				 * IRQ descriptors may have no IRQ# bits set,
 				 * particularly those w/ _STA disabled
···
 		{
 			struct acpi_resource_extended_irq *p =
 			    &resource->data.extended_irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				/*
 				 * extended IRQ descriptors must
 				 * return at least 1 IRQ

drivers/acpi/processor_driver.c

···
 }
 
 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
-static int acpi_pss_perf_init(struct acpi_processor *pr,
-		struct acpi_device *device)
+static void acpi_pss_perf_init(struct acpi_processor *pr)
 {
-	int result = 0;
-
 	acpi_processor_ppc_has_changed(pr, 0);
 
 	acpi_processor_get_throttling_info(pr);
 
 	if (pr->flags.throttling)
 		pr->flags.limit = 1;
-
-	pr->cdev = thermal_cooling_device_register("Processor", device,
-						   &processor_cooling_ops);
-	if (IS_ERR(pr->cdev)) {
-		result = PTR_ERR(pr->cdev);
-		return result;
-	}
-
-	dev_dbg(&device->dev, "registered as cooling_device%d\n",
-		pr->cdev->id);
-
-	result = sysfs_create_link(&device->dev.kobj,
-				   &pr->cdev->device.kobj,
-				   "thermal_cooling");
-	if (result) {
-		dev_err(&device->dev,
-			"Failed to create sysfs link 'thermal_cooling'\n");
-		goto err_thermal_unregister;
-	}
-
-	result = sysfs_create_link(&pr->cdev->device.kobj,
-				   &device->dev.kobj,
-				   "device");
-	if (result) {
-		dev_err(&pr->cdev->device,
-			"Failed to create sysfs link 'device'\n");
-		goto err_remove_sysfs_thermal;
-	}
-
-	return 0;
-
- err_remove_sysfs_thermal:
-	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
- err_thermal_unregister:
-	thermal_cooling_device_unregister(pr->cdev);
-
-	return result;
-}
-
-static void acpi_pss_perf_exit(struct acpi_processor *pr,
-		struct acpi_device *device)
-{
-	if (pr->cdev) {
-		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
-		sysfs_remove_link(&pr->cdev->device.kobj, "device");
-		thermal_cooling_device_unregister(pr->cdev);
-		pr->cdev = NULL;
-	}
 }
 #else
-static inline int acpi_pss_perf_init(struct acpi_processor *pr,
-		struct acpi_device *device)
-{
-	return 0;
-}
-
-static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
-		struct acpi_device *device) {}
+static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
 #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
 
 static int __acpi_processor_start(struct acpi_device *device)
···
 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
 		acpi_processor_power_init(pr);
 
-	result = acpi_pss_perf_init(pr, device);
+	acpi_pss_perf_init(pr);
+
+	result = acpi_processor_thermal_init(pr, device);
 	if (result)
 		goto err_power_exit;
 
···
 		return 0;
 
 	result = -ENODEV;
-	acpi_pss_perf_exit(pr, device);
+	acpi_processor_thermal_exit(pr, device);
 
 err_power_exit:
 	acpi_processor_power_exit(pr);
···
 		return 0;
 	acpi_processor_power_exit(pr);
 
-	acpi_pss_perf_exit(pr, device);
-
 	acpi_cppc_processor_exit(pr);
+
+	acpi_processor_thermal_exit(pr, device);
 
 	return 0;
 }

drivers/acpi/processor_idle.c

···
  * @cx: Target state context
  * @index: index of target state
  */
-static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
+static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
 			       struct acpi_processor *pr,
 			       struct acpi_processor_cx *cx,
 			       int index)
···
 	return index;
 }
 
-static int acpi_idle_enter(struct cpuidle_device *dev,
+static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
 			   struct cpuidle_driver *drv, int index)
 {
 	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
···
 	return index;
 }
 
-static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,
+static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 				  struct cpuidle_driver *drv, int index)
 {
 	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);

drivers/acpi/processor_thermal.c

···
 	.get_cur_state = processor_get_cur_state,
 	.set_cur_state = processor_set_cur_state,
 };
+
+int acpi_processor_thermal_init(struct acpi_processor *pr,
+				struct acpi_device *device)
+{
+	int result = 0;
+
+	pr->cdev = thermal_cooling_device_register("Processor", device,
+						   &processor_cooling_ops);
+	if (IS_ERR(pr->cdev)) {
+		result = PTR_ERR(pr->cdev);
+		return result;
+	}
+
+	dev_dbg(&device->dev, "registered as cooling_device%d\n",
+		pr->cdev->id);
+
+	result = sysfs_create_link(&device->dev.kobj,
+				   &pr->cdev->device.kobj,
+				   "thermal_cooling");
+	if (result) {
+		dev_err(&device->dev,
+			"Failed to create sysfs link 'thermal_cooling'\n");
+		goto err_thermal_unregister;
+	}
+
+	result = sysfs_create_link(&pr->cdev->device.kobj,
+				   &device->dev.kobj,
+				   "device");
+	if (result) {
+		dev_err(&pr->cdev->device,
+			"Failed to create sysfs link 'device'\n");
+		goto err_remove_sysfs_thermal;
+	}
+
+	return 0;
+
+err_remove_sysfs_thermal:
+	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+err_thermal_unregister:
+	thermal_cooling_device_unregister(pr->cdev);
+
+	return result;
+}
+
+void acpi_processor_thermal_exit(struct acpi_processor *pr,
+				 struct acpi_device *device)
+{
+	if (pr->cdev) {
+		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+		sysfs_remove_link(&pr->cdev->device.kobj, "device");
+		thermal_cooling_device_unregister(pr->cdev);
+		pr->cdev = NULL;
+	}
+}

drivers/acpi/property.c

···
 				   propname, proptype, val, nval);
 }
 
+static int stop_on_next(struct acpi_device *adev, void *data)
+{
+	struct acpi_device **ret_p = data;
+
+	if (!*ret_p) {
+		*ret_p = adev;
+		return 1;
+	}
+
+	/* Skip until the "previous" object is found. */
+	if (*ret_p == adev)
+		*ret_p = NULL;
+
+	return 0;
+}
+
 /**
  * acpi_get_next_subnode - Return the next child node handle for a fwnode
  * @fwnode: Firmware node to find the next child node for.
···
 struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode,
 					    struct fwnode_handle *child)
 {
-	const struct acpi_device *adev = to_acpi_device_node(fwnode);
-	const struct list_head *head;
-	struct list_head *next;
+	struct acpi_device *adev = to_acpi_device_node(fwnode);
 
 	if ((!child || is_acpi_device_node(child)) && adev) {
-		struct acpi_device *child_adev;
+		struct acpi_device *child_adev = to_acpi_device_node(child);
 
-		head = &adev->children;
-		if (list_empty(head))
-			goto nondev;
+		acpi_dev_for_each_child(adev, stop_on_next, &child_adev);
+		if (child_adev)
+			return acpi_fwnode_handle(child_adev);
 
-		if (child) {
-			adev = to_acpi_device_node(child);
-			next = adev->node.next;
-			if (next == head) {
-				child = NULL;
-				goto nondev;
-			}
-			child_adev = list_entry(next, struct acpi_device, node);
-		} else {
-			child_adev = list_first_entry(head, struct acpi_device,
-						      node);
-		}
-		return acpi_fwnode_handle(child_adev);
+		child = NULL;
 	}
 
- nondev:
 	if (!child || is_acpi_data_node(child)) {
 		const struct acpi_data_node *data = to_acpi_data_node(fwnode);
+		const struct list_head *head;
+		struct list_head *next;
 		struct acpi_data_node *dn;
 
 		/*

drivers/acpi/resource.c

···
 {
 	int i;
 
+#ifdef CONFIG_X86
+	/*
+	 * IRQ override isn't needed on modern AMD Zen systems and
+	 * this override breaks active low IRQs on AMD Ryzen 6000 and
+	 * newer systems. Skip it.
+	 */
+	if (boot_cpu_has(X86_FEATURE_ZEN))
+		return false;
+#endif
+
 	for (i = 0; i < ARRAY_SIZE(skip_override_table); i++) {
 		const struct irq_override_cmp *entry = &skip_override_table[i];
 

drivers/acpi/scan.c

···
 	return error;
 }
 
-static int acpi_scan_bus_check(struct acpi_device *adev)
+static int acpi_scan_bus_check(struct acpi_device *adev, void *not_used)
 {
 	struct acpi_scan_handler *handler = adev->handler;
-	struct acpi_device *child;
 	int error;
 
 	acpi_bus_get_status(adev);
···
 		dev_warn(&adev->dev, "Namespace scan failure\n");
 		return error;
 	}
-	list_for_each_entry(child, &adev->children, node) {
-		error = acpi_scan_bus_check(child);
-		if (error)
-			return error;
-	}
-	return 0;
+	return acpi_dev_for_each_child(adev, acpi_scan_bus_check, NULL);
 }
 
 static int acpi_generic_hotplug_event(struct acpi_device *adev, u32 type)
 {
 	switch (type) {
 	case ACPI_NOTIFY_BUS_CHECK:
-		return acpi_scan_bus_check(adev);
+		return acpi_scan_bus_check(adev, NULL);
 	case ACPI_NOTIFY_DEVICE_CHECK:
 		return acpi_scan_device_check(adev);
 	case ACPI_NOTIFY_EJECT_REQUEST:
···
 	struct acpi_device_bus_id *acpi_device_bus_id;
 
 	mutex_lock(&acpi_device_lock);
-	if (device->parent)
-		list_del(&device->node);
 
 	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
 		if (!strcmp(acpi_device_bus_id->bus_id,
···
 		}
 
 	list_del(&device->wakeup_list);
+
 	mutex_unlock(&acpi_device_lock);
 
 	acpi_power_add_remove_device(device, false);
···
 	 * -------
 	 * Link this device to its parent and siblings.
 	 */
-	INIT_LIST_HEAD(&device->children);
-	INIT_LIST_HEAD(&device->node);
 	INIT_LIST_HEAD(&device->wakeup_list);
 	INIT_LIST_HEAD(&device->physical_node_list);
 	INIT_LIST_HEAD(&device->del_list);
···
 		list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
 	}
 
-	if (device->parent)
-		list_add_tail(&device->node, &device->parent->children);
-
 	if (device->wakeup.flags.valid)
 		list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 
···
 
 err:
 	mutex_lock(&acpi_device_lock);
-
-	if (device->parent)
-		list_del(&device->node);
 
 	list_del(&device->wakeup_list);
 
···
 	return ret;
 }
 
-static void acpi_bus_attach(struct acpi_device *device, bool first_pass)
+static int acpi_bus_attach(struct acpi_device *device, void *first_pass)
 {
-	struct acpi_device *child;
 	bool skip = !first_pass && device->flags.visited;
 	acpi_handle ejd;
 	int ret;
···
 		device->flags.initialized = false;
 		acpi_device_clear_enumerated(device);
 		device->flags.power_manageable = 0;
-		return;
+		return 0;
 	}
 	if (device->handler)
 		goto ok;
···
 
 	ret = acpi_scan_attach_handler(device);
 	if (ret < 0)
-		return;
+		return 0;
 
 	device->flags.match_driver = true;
 	if (ret > 0 && !device->flags.enumeration_by_parent) {
···
 
 	ret = device_attach(&device->dev);
 	if (ret < 0)
-		return;
+		return 0;
 
 	if (device->pnp.type.platform_id || device->flags.enumeration_by_parent)
 		acpi_default_enumeration(device);
 	else
 		acpi_device_set_enumerated(device);
 
- ok:
-	list_for_each_entry(child, &device->children, node)
-		acpi_bus_attach(child, first_pass);
+ok:
+	acpi_dev_for_each_child(device, acpi_bus_attach, first_pass);
 
 	if (!skip && device->handler && device->handler->hotplug.notify_online)
 		device->handler->hotplug.notify_online(device);
+
+	return 0;
 }
 
 static int acpi_dev_get_first_consumer_dev_cb(struct acpi_dep_data *dep, void *data)
···
 	cdw = container_of(work, struct acpi_scan_clear_dep_work, work);
 
 	acpi_scan_lock_acquire();
-	acpi_bus_attach(cdw->adev, true);
+	acpi_bus_attach(cdw->adev, (void *)true);
 	acpi_scan_lock_release();
 
 	acpi_dev_put(cdw->adev);
···
 	if (!device)
 		return -ENODEV;
 
-	acpi_bus_attach(device, true);
+	acpi_bus_attach(device, (void *)true);
 
 	if (!acpi_bus_scan_second_pass)
 		return 0;
···
 				    acpi_bus_check_add_2, NULL, NULL,
 				    (void **)&device);
 
-	acpi_bus_attach(device, false);
+	acpi_bus_attach(device, NULL);
 
 	return 0;
 }
 EXPORT_SYMBOL(acpi_bus_scan);
 
-/**
- * acpi_bus_trim - Detach scan handlers and drivers from ACPI device objects.
- * @adev: Root of the ACPI namespace scope to walk.
- *
- * Must be called under acpi_scan_lock.
- */
-void acpi_bus_trim(struct acpi_device *adev)
+static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
 {
 	struct acpi_scan_handler *handler = adev->handler;
-	struct acpi_device *child;
 
-	list_for_each_entry_reverse(child, &adev->children, node)
-		acpi_bus_trim(child);
+	acpi_dev_for_each_child_reverse(adev, acpi_bus_trim_one, NULL);
 
 	adev->flags.match_driver = false;
 	if (handler) {
···
 	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
 	adev->flags.initialized = false;
 	acpi_device_clear_enumerated(adev);
+
+	return 0;
+}
+
+/**
+ * acpi_bus_trim - Detach scan handlers and drivers from ACPI device objects.
+ * @adev: Root of the ACPI namespace scope to walk.
+ *
+ * Must be called under acpi_scan_lock.
+ */
+void acpi_bus_trim(struct acpi_device *adev)
+{
+	acpi_bus_trim_one(adev, NULL);
 }
 EXPORT_SYMBOL_GPL(acpi_bus_trim);
 

drivers/acpi/sleep.c

···
 		DMI_MATCH(DMI_PRODUCT_NAME, "80E3"),
 		},
 	},
+	{
+	.callback = init_nvs_save_s3,
+	.ident = "Lenovo G40-45",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "80E1"),
+		},
+	},
 	/*
 	 * ThinkPad X1 Tablet(2016) cannot do suspend-to-idle using
 	 * the Low Power S0 Idle firmware interface (see
···
 
 void __weak acpi_s2idle_setup(void)
 {
+	if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
+		pr_info("Efficient low-power S0 idle declared\n");
+
 	s2idle_set_ops(&acpi_s2idle_ops);
 }
 

drivers/acpi/video_detect.c

···
 	},
 	{
 	 .callback = video_detect_force_native,
+	 /* Dell Inspiron N4010 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+		DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron N4010"),
+		},
+	},
+	{
+	 .callback = video_detect_force_native,
 	 /* Dell Vostro V131 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
···
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xRU",
 	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
-		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
-		},
-	},
-	{
-	.callback = video_detect_force_native,
-	.ident = "Clevo NL5xRU",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "SchenkerTechnologiesGmbH"),
-		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
-		},
-	},
-	{
-	.callback = video_detect_force_native,
-	.ident = "Clevo NL5xRU",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Notebook"),
 		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
 		},
 	},
···
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xNU",
 	.matches = {
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		},
+	},
+	/*
+	 * The TongFang PF5PU1G, PF4NU1F, PF5NU1G, and PF5LUXG/TUXEDO BA15 Gen10,
+	 * Pulse 14/15 Gen1, and Pulse 15 Gen2 have the same problem as the Clevo
+	 * NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description
+	 * above.
+	 */
+	{
+	.callback = video_detect_force_native,
+	.ident = "TongFang PF5PU1G",
+	.matches = {
+		DMI_MATCH(DMI_BOARD_NAME, "PF5PU1G"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "TongFang PF4NU1F",
+	.matches = {
+		DMI_MATCH(DMI_BOARD_NAME, "PF4NU1F"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "TongFang PF4NU1F",
+	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
-		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		DMI_MATCH(DMI_BOARD_NAME, "PULSE1401"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
-	.ident = "Clevo NL5xNU",
+	.ident = "TongFang PF5NU1G",
 	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "SchenkerTechnologiesGmbH"),
-		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		DMI_MATCH(DMI_BOARD_NAME, "PF5NU1G"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
-	.ident = "Clevo NL5xNU",
+	.ident = "TongFang PF5NU1G",
 	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Notebook"),
-		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
+		DMI_MATCH(DMI_BOARD_NAME, "PULSE1501"),
 		},
 	},
-
+	{
+	.callback = video_detect_force_native,
+	.ident = "TongFang PF5LUXG",
+	.matches = {
+		DMI_MATCH(DMI_BOARD_NAME, "PF5LUXG"),
+		},
+	},
 	/*
 	 * Desktops which falsely report a backlight and which our heuristics
 	 * for this do not catch.

drivers/acpi/viot.c

···
 }
 
 /**
+ * acpi_viot_early_init - Test the presence of VIOT and enable ACS
+ *
+ * If the VIOT does exist, ACS must be enabled. This cannot be
+ * done in acpi_viot_init() which is called after the bus scan
+ */
+void __init acpi_viot_early_init(void)
+{
+#ifdef CONFIG_PCI
+	acpi_status status;
+	struct acpi_table_header *hdr;
+
+	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
+	if (ACPI_FAILURE(status))
+		return;
+	pci_request_acs();
+	acpi_put_table(hdr);
+#endif
+}
+
+/**
  * acpi_viot_init - Parse the VIOT table
  *
  * Parse the VIOT table, prepare the list of endpoints to be used during DMA
···
 		    dev_id <= ep->bdf_end) {
 			epid = ((domain_nr - ep->segment_start) << 16) +
 				dev_id - ep->bdf_start + ep->endpoint_id;
-
-			/*
-			 * If we found a PCI range managed by the viommu, we're
-			 * the one that has to request ACS.
-			 */
-			pci_request_acs();
 
 			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
 						   epid);

drivers/acpi/x86/s2idle.c

···
 	if (lps0_device_handle)
 		return 0;
 
-	if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
-		return 0;
-
 	if (acpi_s2idle_vendor_amd()) {
 		/* AMD0004, AMD0005, AMDI0005:
 		 * - Should use rev_id 0x0
···
 			lps0_dsm_func_mask = (lps0_dsm_func_mask << 1) | 0x1;
 			acpi_handle_debug(adev->handle, "_DSM UUID %s: Adjusted function mask: 0x%x\n",
 					  ACPI_LPS0_DSM_UUID_AMD, lps0_dsm_func_mask);
-		} else if (lps0_dsm_func_mask_microsoft > 0 && !strcmp(hid, "AMDI0007")) {
+		} else if (lps0_dsm_func_mask_microsoft > 0 &&
+				(!strcmp(hid, "AMDI0007") ||
+				 !strcmp(hid, "AMDI0008"))) {
 			lps0_dsm_func_mask_microsoft = -EINVAL;
 			acpi_handle_debug(adev->handle, "_DSM Using AMD method\n");
 		}
···
 		lpi_device_get_constraints();
 
 	/*
-	 * Use suspend-to-idle by default if the default suspend mode was not
-	 * set from the command line.
+	 * Use suspend-to-idle by default if ACPI_FADT_LOW_POWER_S0 is set in
+	 * the FADT and the default suspend mode was not set from the command
+	 * line.
 	 */
-	if (mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3)
+	if ((acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0) &&
+	    mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3) {
 		mem_sleep_current = PM_SUSPEND_TO_IDLE;
+		pr_info("Low-power S0 idle used by default for system suspend\n");
+	}
 
 	/*
 	 * Some LPS0 systems, like ASUS Zenbook UX430UNR/i7-8550U, require the

drivers/bus/hisi_lpc.c

···
 
 /*
  * hisi_lpc_acpi_set_io_res - set the resources for a child
- * @child: the device node to be updated the I/O resource
+ * @adev: ACPI companion of the device node to be updated the I/O resource
  * @hostdev: the device node associated with host controller
  * @res: double pointer to be set to the address of translated resources
  * @num_res: pointer to variable to hold the number of translated resources
···
  * host-relative address resource.  This function will return the translated
  * logical PIO addresses for each child devices resources.
  */
-static int hisi_lpc_acpi_set_io_res(struct device *child,
+static int hisi_lpc_acpi_set_io_res(struct acpi_device *adev,
 				    struct device *hostdev,
 				    const struct resource **res, int *num_res)
 {
-	struct acpi_device *adev;
-	struct acpi_device *host;
+	struct acpi_device *host = to_acpi_device(adev->dev.parent);
 	struct resource_entry *rentry;
 	LIST_HEAD(resource_list);
 	struct resource *resources;
 	int count;
 	int i;
 
-	if (!child || !hostdev)
-		return -EINVAL;
-
-	host = to_acpi_device(hostdev);
-	adev = to_acpi_device(child);
-
 	if (!adev->status.present) {
-		dev_dbg(child, "device is not present\n");
+		dev_dbg(&adev->dev, "device is not present\n");
 		return -EIO;
 	}
 
 	if (acpi_device_enumerated(adev)) {
-		dev_dbg(child, "has been enumerated\n");
+		dev_dbg(&adev->dev, "has been enumerated\n");
 		return -EIO;
 	}
 
···
 	 */
 	count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
 	if (count <= 0) {
-		dev_dbg(child, "failed to get resources\n");
+		dev_dbg(&adev->dev, "failed to get resources\n");
 		return count ? count : -EIO;
 	}
 
···
 			continue;
 		ret = hisi_lpc_acpi_xlat_io_res(adev, host, &resources[i]);
 		if (ret) {
-			dev_err(child, "translate IO range %pR failed (%d)\n",
+			dev_err(&adev->dev, "translate IO range %pR failed (%d)\n",
 				&resources[i], ret);
 			return ret;
 		}
···
 	return 0;
 }
 
+static int hisi_lpc_acpi_clear_enumerated(struct acpi_device *adev, void *not_used)
+{
+	acpi_device_clear_enumerated(adev);
+	return 0;
+}
+
 struct hisi_lpc_acpi_cell {
 	const char *hid;
 	const char *name;
···
 
 static void hisi_lpc_acpi_remove(struct device *hostdev)
 {
-	struct acpi_device *adev = ACPI_COMPANION(hostdev);
-	struct acpi_device *child;
-
 	device_for_each_child(hostdev, NULL, hisi_lpc_acpi_remove_subdev);
+	acpi_dev_for_each_child(ACPI_COMPANION(hostdev),
+				hisi_lpc_acpi_clear_enumerated, NULL);
+}
 
-	list_for_each_entry(child, &adev->children, node)
-		acpi_device_clear_enumerated(child);
+static int hisi_lpc_acpi_add_child(struct acpi_device *child, void *data)
+{
+	const char *hid = acpi_device_hid(child);
+	struct device *hostdev = data;
+	const struct hisi_lpc_acpi_cell *cell;
+	struct platform_device *pdev;
+	const struct resource *res;
+	bool found = false;
+	int num_res;
+	int ret;
+
+	ret = hisi_lpc_acpi_set_io_res(child, hostdev, &res, &num_res);
+	if (ret) {
+		dev_warn(hostdev, "set resource fail (%d)\n", ret);
+		return ret;
+	}
+
+	cell = (struct hisi_lpc_acpi_cell []){
+		/* ipmi */
+		{
+			.hid = "IPI0001",
+			.name = "hisi-lpc-ipmi",
+		},
+		/* 8250-compatible uart */
+		{
+			.hid = "HISI1031",
+			.name = "serial8250",
+			.pdata = (struct plat_serial8250_port []) {
+				{
+					.iobase = res->start,
+					.uartclk = 1843200,
+					.iotype = UPIO_PORT,
+					.flags = UPF_BOOT_AUTOCONF,
+				},
+				{}
+			},
+			.pdata_size = 2 *
+				sizeof(struct plat_serial8250_port),
+		},
+		{}
+	};
+
+	for (; cell && cell->name; cell++) {
+		if (!strcmp(cell->hid, hid)) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		dev_warn(hostdev,
+			 "could not find cell for child device (%s), discarding\n",
+			 hid);
+		return 0;
+	}
+
+	pdev = platform_device_alloc(cell->name, PLATFORM_DEVID_AUTO);
+	if (!pdev)
+		return -ENOMEM;
+
+	pdev->dev.parent = hostdev;
+	ACPI_COMPANION_SET(&pdev->dev, child);
+
+	ret = platform_device_add_resources(pdev, res, num_res);
+	if (ret)
+		goto fail;
+
+	ret = platform_device_add_data(pdev, cell->pdata, cell->pdata_size);
+	if (ret)
+		goto fail;
+
+	ret = platform_device_add(pdev);
+	if (ret)
+		goto fail;
+
+	acpi_device_set_enumerated(child);
+	return 0;
+
+fail:
+	platform_device_put(pdev);
+	return ret;
 }
 
 /*
···
  */
 static int hisi_lpc_acpi_probe(struct device *hostdev)
 {
-	struct acpi_device *adev = ACPI_COMPANION(hostdev);
-	struct acpi_device *child;
 	int ret;
 
 	/* Only consider the children of the host */
-	list_for_each_entry(child, &adev->children, node) {
-		const char *hid = acpi_device_hid(child);
-		const struct hisi_lpc_acpi_cell *cell;
-		struct platform_device *pdev;
-		const struct resource *res;
-		bool found = false;
-		int num_res;
+	ret = acpi_dev_for_each_child(ACPI_COMPANION(hostdev),
+				      hisi_lpc_acpi_add_child, hostdev);
+	if (ret)
+		hisi_lpc_acpi_remove(hostdev);
 
-		ret = hisi_lpc_acpi_set_io_res(&child->dev, &adev->dev, &res,
-					       &num_res);
-		if (ret) {
-			dev_warn(hostdev, "set resource fail (%d)\n", ret);
-			goto fail;
-		}
-
-		cell = (struct hisi_lpc_acpi_cell []){
-			/* ipmi */
-			{
-				.hid = "IPI0001",
-				.name = "hisi-lpc-ipmi",
-			},
-			/* 8250-compatible uart */
-			{
-				.hid = "HISI1031",
-				.name = "serial8250",
-				.pdata = (struct plat_serial8250_port []) {
-					{
-						.iobase = res->start,
-						.uartclk = 1843200,
-						.iotype = UPIO_PORT,
-						.flags = UPF_BOOT_AUTOCONF,
-					},
-					{}
-				},
-				.pdata_size = 2 *
-					sizeof(struct plat_serial8250_port),
-			},
-			{}
-		};
-
-		for (; cell && cell->name; cell++) {
-			if (!strcmp(cell->hid, hid)) {
-				found = true;
-				break;
-			}
-		}
-
-		if (!found) {
-			dev_warn(hostdev,
-				 "could not find cell for child device (%s), discarding\n",
-				 hid);
-			continue;
-		}
-
-		pdev = platform_device_alloc(cell->name, PLATFORM_DEVID_AUTO);
-		if (!pdev) {
-			ret = -ENOMEM;
-			goto fail;
-		}
-
-		pdev->dev.parent = hostdev;
-		ACPI_COMPANION_SET(&pdev->dev, child);
-
-		ret = platform_device_add_resources(pdev, res, num_res);
-		if (ret)
-			goto fail;
-
-		ret = platform_device_add_data(pdev, cell->pdata,
-					       cell->pdata_size);
-		if (ret)
-			goto fail;
-
-		ret = platform_device_add(pdev);
-		if (ret)
-			goto fail;
-
-		acpi_device_set_enumerated(child);
-	}
-
-	return 0;
-
-fail:
-	hisi_lpc_acpi_remove(hostdev);
 	return ret;
 }
 

drivers/mfd/mfd-core.c

···
 EXPORT_SYMBOL(mfd_cell_disable);
 
 #if IS_ENABLED(CONFIG_ACPI)
+struct match_ids_walk_data {
+	struct acpi_device_id *ids;
+	struct acpi_device *adev;
+};
+
+static int match_device_ids(struct acpi_device *adev, void *data)
+{
+	struct match_ids_walk_data *wd = data;
+
+	if (!acpi_match_device_ids(adev, wd->ids)) {
+		wd->adev = adev;
+		return 1;
+	}
+
+	return 0;
+}
+
 static void mfd_acpi_add_device(const struct mfd_cell *cell,
 				struct platform_device *pdev)
 {
 	const struct mfd_cell_acpi_match *match = cell->acpi_match;
-	struct acpi_device *parent, *child;
 	struct acpi_device *adev = NULL;
+	struct acpi_device *parent;
 
 	parent = ACPI_COMPANION(pdev->dev.parent);
 	if (!parent)
···
 	if (match) {
 		if (match->pnpid) {
 			struct acpi_device_id ids[2] = {};
+			struct match_ids_walk_data wd = {
+				.adev = NULL,
+				.ids = ids,
+			};
 
 			strlcpy(ids[0].id, match->pnpid, sizeof(ids[0].id));
-			list_for_each_entry(child, &parent->children, node) {
-				if (!acpi_match_device_ids(child, ids)) {
-					adev = child;
-					break;
-				}
-			}
+			acpi_dev_for_each_child(parent, match_device_ids, &wd);
+			adev = wd.adev;
 		} else {
 			adev = acpi_find_child_device(parent, match->adr, false);
 		}

drivers/mmc/host/sdhci-acpi.c

···
 {
 	struct device *dev = &pdev->dev;
 	const struct sdhci_acpi_slot *slot;
-	struct acpi_device *device, *child;
 	const struct dmi_system_id *id;
+	struct acpi_device *device;
 	struct sdhci_acpi_host *c;
 	struct sdhci_host *host;
 	struct resource *iomem;
···
 	slot = sdhci_acpi_get_slot(device);
 
 	/* Power on the SDHCI controller and its children */
-	acpi_device_fix_up_power(device);
-	list_for_each_entry(child, &device->children, node)
-		if (child->status.present && child->status.enabled)
-			acpi_device_fix_up_power(child);
+	acpi_device_fix_up_power_extended(device);
 
 	if (sdhci_acpi_byt_defer(dev))
 		return -EPROBE_DEFER;

drivers/mmc/host/sdhci-pci-core.c

···
 #ifdef CONFIG_ACPI
 static void intel_mrfld_mmc_fix_up_power_slot(struct sdhci_pci_slot *slot)
 {
-	struct acpi_device *device, *child;
+	struct acpi_device *device;
 
 	device = ACPI_COMPANION(&slot->chip->pdev->dev);
-	if (!device)
-		return;
-
-	acpi_device_fix_up_power(device);
-	list_for_each_entry(child, &device->children, node)
-		if (child->status.present && child->status.enabled)
-			acpi_device_fix_up_power(child);
+	if (device)
+		acpi_device_fix_up_power_extended(device);
 }
 #else
 static inline void intel_mrfld_mmc_fix_up_power_slot(struct sdhci_pci_slot *slot) {}

drivers/platform/x86/thinkpad_acpi.c

···
 
 /* --------------------------------------------------------------------- */
 
+static int __init tpacpi_evaluate_bcl(struct acpi_device *adev, void *not_used)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	acpi_status status;
+	int rc;
+
+	status = acpi_evaluate_object(adev->handle, "_BCL", NULL, &buffer);
+	if (ACPI_FAILURE(status))
+		return 0;
+
+	obj = buffer.pointer;
+	if (!obj || obj->type != ACPI_TYPE_PACKAGE) {
+		acpi_handle_info(adev->handle,
+				 "Unknown _BCL data, please report this to %s\n",
+				 TPACPI_MAIL);
+		rc = 0;
+	} else {
+		rc = obj->package.count;
+	}
+	kfree(obj);
+
+	return rc;
+}
+
 /*
  * Call _BCL method of video device.  On some ThinkPads this will
  * switch the firmware to the ACPI brightness control mode.
···
 
 static int __init tpacpi_query_bcl_levels(acpi_handle handle)
 {
-	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *obj;
-	struct acpi_device *device, *child;
-	int rc;
+	struct acpi_device *device;
 
 	device = acpi_fetch_acpi_dev(handle);
 	if (!device)
 		return 0;
 
-	rc = 0;
-	list_for_each_entry(child, &device->children, node) {
-		acpi_status status = acpi_evaluate_object(child->handle, "_BCL",
-							  NULL, &buffer);
-		if (ACPI_FAILURE(status)) {
-			buffer.length = ACPI_ALLOCATE_BUFFER;
-			continue;
-		}
-
-		obj = (union acpi_object *)buffer.pointer;
-		if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
-			pr_err("Unknown _BCL data, please report this to %s\n",
-				TPACPI_MAIL);
-			rc = 0;
-		} else {
-			rc = obj->package.count;
-		}
-		break;
-	}
-
-	kfree(buffer.pointer);
-	return rc;
+	return acpi_dev_for_each_child(device, tpacpi_evaluate_bcl, NULL);
 }
 
 

drivers/soundwire/slave.c

···
 	return true;
 }
 
+struct sdw_acpi_child_walk_data {
+	struct sdw_bus *bus;
+	struct acpi_device *adev;
+	struct sdw_slave_id id;
+	bool ignore_unique_id;
+};
+
+static int sdw_acpi_check_duplicate(struct acpi_device *adev, void *data)
+{
+	struct sdw_acpi_child_walk_data *cwd = data;
+	struct sdw_bus *bus = cwd->bus;
+	struct sdw_slave_id id;
+
+	if (adev == cwd->adev)
+		return 0;
+
+	if (!find_slave(bus, adev, &id))
+		return 0;
+
+	if (cwd->id.sdw_version != id.sdw_version || cwd->id.mfg_id != id.mfg_id ||
+	    cwd->id.part_id != id.part_id || cwd->id.class_id != id.class_id)
+		return 0;
+
+	if (cwd->id.unique_id != id.unique_id) {
+		dev_dbg(bus->dev,
+			"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
+			cwd->id.unique_id, id.unique_id, cwd->id.mfg_id,
+			cwd->id.part_id);
+		cwd->ignore_unique_id = false;
+		return 0;
+	}
+
+	dev_err(bus->dev,
+		"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
+		cwd->id.unique_id, id.unique_id, cwd->id.mfg_id, cwd->id.part_id);
+	return -ENODEV;
+}
+
+static int sdw_acpi_find_one(struct acpi_device *adev, void *data)
+{
+	struct sdw_bus *bus = data;
+	struct sdw_acpi_child_walk_data cwd = {
+		.bus = bus,
+		.adev = adev,
+		.ignore_unique_id = true,
+	};
+	int ret;
+
+	if (!find_slave(bus, adev, &cwd.id))
+		return 0;
+
+	/* Brute-force O(N^2) search for duplicates. */
+	ret = acpi_dev_for_each_child(ACPI_COMPANION(bus->dev),
+				      sdw_acpi_check_duplicate, &cwd);
+	if (ret)
+		return ret;
+
+	if (cwd.ignore_unique_id)
+		cwd.id.unique_id = SDW_IGNORED_UNIQUE_ID;
+
+	/* Ignore errors and continue. */
+	sdw_slave_add(bus, &cwd.id, acpi_fwnode_handle(adev));
+	return 0;
+}
+
 /*
  * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
  * @bus: SDW bus instance
···
  */
 int sdw_acpi_find_slaves(struct sdw_bus *bus)
 {
-	struct acpi_device *adev, *parent;
-	struct acpi_device *adev2, *parent2;
+	struct acpi_device *parent;
 
 	parent = ACPI_COMPANION(bus->dev);
 	if (!parent) {
···
 		return -ENODEV;
 	}
 
-	list_for_each_entry(adev, &parent->children, node) {
-		struct sdw_slave_id id;
-		struct sdw_slave_id id2;
-		bool ignore_unique_id = true;
-
-		if (!find_slave(bus, adev, &id))
-			continue;
-
-		/* brute-force O(N^2) search for duplicates */
-		parent2 = parent;
-		list_for_each_entry(adev2, &parent2->children, node) {
-
-			if (adev == adev2)
-				continue;
-
-			if (!find_slave(bus, adev2, &id2))
-				continue;
-
-			if (id.sdw_version != id2.sdw_version ||
-			    id.mfg_id != id2.mfg_id ||
-			    id.part_id != id2.part_id ||
-			    id.class_id != id2.class_id)
-				continue;
-
-			if (id.unique_id != id2.unique_id) {
-				dev_dbg(bus->dev,
-					"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
-					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
-				ignore_unique_id = false;
-			} else {
-				dev_err(bus->dev,
-					"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
-					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
-				return -ENODEV;
-			}
-		}
-
-		if (ignore_unique_id)
-			id.unique_id = SDW_IGNORED_UNIQUE_ID;
-
-		/*
-		 * don't error check for sdw_slave_add as we want to continue
-		 * adding Slaves
-		 */
-		sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
-	}
-
-	return 0;
+	return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
 }
 
 #endif

drivers/thunderbolt/acpi.c

···
 	return tb_is_switch(dev) || tb_is_usb4_port_device(dev);
 }
 
-static struct acpi_device *tb_acpi_find_port(struct acpi_device *adev,
-					     const struct tb_port *port)
-{
-	struct acpi_device *port_adev;
-
-	if (!adev)
-		return NULL;
-
-	/*
-	 * Device routers exists under the downstream facing USB4 port
-	 * of the parent router. Their _ADR is always 0.
-	 */
-	list_for_each_entry(port_adev, &adev->children, node) {
-		if (acpi_device_adr(port_adev) == port->port)
-			return port_adev;
-	}
-
-	return NULL;
-}
-
 static struct acpi_device *tb_acpi_switch_find_companion(struct tb_switch *sw)
 {
 	struct acpi_device *adev = NULL;
 	struct tb_switch *parent_sw;
 
+	/*
+	 * Device routers exists under the downstream facing USB4 port
+	 * of the parent router. Their _ADR is always 0.
+	 */
 	parent_sw = tb_switch_parent(sw);
 	if (parent_sw) {
 		struct tb_port *port = tb_port_at(tb_route(sw), parent_sw);
 		struct acpi_device *port_adev;
 
-		port_adev = tb_acpi_find_port(ACPI_COMPANION(&parent_sw->dev), port);
+		port_adev = acpi_find_child_by_adr(ACPI_COMPANION(&parent_sw->dev),
+						   port->port);
 		if (port_adev)
 			adev = acpi_find_child_device(port_adev, 0, false);
 	} else {
···
 	if (tb_is_switch(dev))
 		return tb_acpi_switch_find_companion(tb_to_switch(dev));
 	else if (tb_is_usb4_port_device(dev))
-		return tb_acpi_find_port(ACPI_COMPANION(dev->parent),
-					 tb_to_usb4_port_device(dev)->port);
+		return acpi_find_child_by_adr(ACPI_COMPANION(dev->parent),
+					      tb_to_usb4_port_device(dev)->port->port);
 	return NULL;
 }
 

drivers/usb/core/usb-acpi.c

···
  */
 #define USB_ACPI_LOCATION_VALID (1 << 31)
 
-static struct acpi_device *usb_acpi_find_port(struct acpi_device *parent,
-					      int raw)
-{
-	struct acpi_device *adev;
-
-	if (!parent)
-		return NULL;
-
-	list_for_each_entry(adev, &parent->children, node) {
-		if (acpi_device_adr(adev) == raw)
-			return adev;
-	}
-
-	return acpi_find_child_device(parent, raw, false);
-}
-
 static struct acpi_device *
 usb_acpi_get_companion_for_port(struct usb_port *port_dev)
 {
···
 		port1 = port_dev->portnum;
 	}
 
-	return usb_acpi_find_port(adev, port1);
+	return acpi_find_child_by_adr(adev, port1);
 }
 
 static struct acpi_device *

include/acpi/acpi_bus.h

···
 	acpi_handle handle;		/* no handle for fixed hardware */
 	struct fwnode_handle fwnode;
 	struct acpi_device *parent;
-	struct list_head children;
-	struct list_head node;
 	struct list_head wakeup_list;
 	struct list_head del_list;
 	struct acpi_device_status status;
···
 	struct acpi_device_data data;
 	struct acpi_scan_handler *handler;
 	struct acpi_hotplug_context *hp;
-	struct acpi_driver *driver;
 	const struct acpi_gpio_mapping *driver_gpios;
 	void *driver_data;
 	struct device dev;
···
 int acpi_bus_for_each_dev(int (*fn)(struct device *, void *), void *data);
 int acpi_dev_for_each_child(struct acpi_device *adev,
 			    int (*fn)(struct acpi_device *, void *), void *data);
+int acpi_dev_for_each_child_reverse(struct acpi_device *adev,
+				    int (*fn)(struct acpi_device *, void *),
+				    void *data);
 
 /*
  * Events
···
 int acpi_device_set_power(struct acpi_device *device, int state);
 int acpi_bus_init_power(struct acpi_device *device);
 int acpi_device_fix_up_power(struct acpi_device *device);
+void acpi_device_fix_up_power_extended(struct acpi_device *adev);
 int acpi_bus_update_power(acpi_handle handle, int *state_p);
 int acpi_device_update_power(struct acpi_device *device, int *state_p);
 bool acpi_bus_power_manageable(acpi_handle handle);
···
 }
 struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
 					   u64 address, bool check_children);
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr);
 int acpi_is_root_bridge(acpi_handle);
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle);
 

include/acpi/cppc_acpi.h

···
 #include <acpi/pcc.h>
 #include <acpi/processor.h>
 
-/* Support CPPCv2 and CPPCv3  */
+/* CPPCv2 and CPPCv3 support */
 #define CPPC_V2_REV	2
 #define CPPC_V3_REV	3
 #define CPPC_V2_NUM_ENT	21

include/acpi/processor.h

···
 #endif /* CONFIG_ACPI_PROCESSOR_IDLE */
 
 /* in processor_thermal.c */
-int acpi_processor_get_limit_info(struct acpi_processor *pr);
+int acpi_processor_thermal_init(struct acpi_processor *pr,
+				struct acpi_device *device);
+void acpi_processor_thermal_exit(struct acpi_processor *pr,
+				 struct acpi_device *device);
 extern const struct thermal_cooling_device_ops processor_cooling_ops;
-#if defined(CONFIG_ACPI_CPU_FREQ_PSS) & defined(CONFIG_CPU_FREQ)
+#ifdef CONFIG_CPU_FREQ
 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy);
 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy);
 #else
···
 {
 	return;
 }
-#endif	/* CONFIG_ACPI_CPU_FREQ_PSS */
+#endif	/* CONFIG_CPU_FREQ */
 
 #endif

include/linux/acpi_viot.h

···
 #include <linux/acpi.h>
 
 #ifdef CONFIG_ACPI_VIOT
+void __init acpi_viot_early_init(void);
 void __init acpi_viot_init(void);
 int viot_iommu_configure(struct device *dev);
 #else
+static inline void acpi_viot_early_init(void) {}
 static inline void acpi_viot_init(void) {}
 static inline int viot_iommu_configure(struct device *dev)
 {