Merge branches 'acpi-scan', 'acpi-pm', 'acpi-power' and 'acpi-pci'

Merge ACPI device enumeration updates, ACPI power management updates
and PCI host bridge ACPI driver updates for 5.17-rc1:

 - Introduce acpi_fetch_acpi_dev() as a replacement for
   acpi_bus_get_device() and use it in the ACPI subsystem (Rafael
   Wysocki).

 - Avoid using _CID for device enumaration if _HID is missing or
   invalid (Rafael Wysocki).

 - Rework quirk handling during ACPI device enumeration and add some
   new quirks for known broken platforms (Hans de Goede).

 - Avoid unnecessary or redundant CPU cache flushing during system
   PM transitions (Kirill A. Shutemov).

 - Add PM debug messages related to power resources (Rafael Wysocki).

 - Fix kernel-doc comment in the PCI host bridge ACPI driver (Yang Li).

* acpi-scan:
  serdev: Do not instantiate serdevs on boards with known bogus DSDT entries
  i2c: acpi: Do not instantiate I2C-clients on boards with known bogus DSDT entries
  ACPI / x86: Add acpi_quirk_skip_[i2c_client|serdev]_enumeration() helpers
  ACPI: scan: Create platform device for BCM4752 and LNV4752 ACPI nodes
  ACPI: Use acpi_fetch_acpi_dev() instead of acpi_bus_get_device()
  ACPI: scan: Introduce acpi_fetch_acpi_dev()
  ACPI: scan: Do not add device IDs from _CID if _HID is not valid

* acpi-pm:
  ACPI: PM: Remove redundant cache flushing
  ACPI: PM: Avoid CPU cache flush when entering S4

* acpi-power:
  ACPI: PM: Emit debug messages when enabling/disabling wakeup power

* acpi-pci:
  PCI/ACPI: Fix acpi_pci_osc_control_set() kernel-doc comment

drivers/acpi/acpi_video.c

@@ -1733,13 +1733,12 @@ acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
 {
 	struct acpi_device *device = context;
 	struct acpi_device *sibling;
-	int result;
 
 	if (handle == device->handle)
 		return AE_CTRL_TERMINATE;
 
-	result = acpi_bus_get_device(handle, &sibling);
-	if (result)
+	sibling = acpi_fetch_acpi_dev(handle);
+	if (!sibling)
 		return AE_OK;
 
 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))

drivers/acpi/device_pm.c

@@ -285,14 +285,12 @@ EXPORT_SYMBOL(acpi_device_set_power);
 
 int acpi_bus_set_power(acpi_handle handle, int state)
 {
-	struct acpi_device *device;
-	int result;
-
-	result = acpi_bus_get_device(handle, &device);
-	if (result)
-		return result;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 
+	if (device)
 		return acpi_device_set_power(device, state);
+
+	return -ENODEV;
 }
 EXPORT_SYMBOL(acpi_bus_set_power);
 
@@ -410,21 +408,20 @@ EXPORT_SYMBOL_GPL(acpi_device_update_power);
 
 int acpi_bus_update_power(acpi_handle handle, int *state_p)
 {
-	struct acpi_device *device;
-	int result;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
+
+	if (device)
+		return acpi_device_update_power(device, state_p);
 
-	result = acpi_bus_get_device(handle, &device);
-	return result ? result : acpi_device_update_power(device, state_p);
+	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(acpi_bus_update_power);
 
 bool acpi_bus_power_manageable(acpi_handle handle)
 {
-	struct acpi_device *device;
-	int result;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 
-	result = acpi_bus_get_device(handle, &device);
-	return result ? false : device->flags.power_manageable;
+	return device && device->flags.power_manageable;
 }
 EXPORT_SYMBOL(acpi_bus_power_manageable);
 
@@ -543,11 +540,9 @@ acpi_status acpi_remove_pm_notifier(struct acpi_device *adev)
 
 bool acpi_bus_can_wakeup(acpi_handle handle)
 {
-	struct acpi_device *device;
-	int result;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 
-	result = acpi_bus_get_device(handle, &device);
-	return result ? false : device->wakeup.flags.valid;
+	return device && device->wakeup.flags.valid;
 }
 EXPORT_SYMBOL(acpi_bus_can_wakeup);
 

drivers/acpi/dock.c

@@ -489,9 +489,8 @@ static ssize_t docked_show(struct device *dev,
 			   struct device_attribute *attr, char *buf)
 {
 	struct dock_station *dock_station = dev->platform_data;
-	struct acpi_device *adev = NULL;
+	struct acpi_device *adev = acpi_fetch_acpi_dev(dock_station->handle);
 
-	acpi_bus_get_device(dock_station->handle, &adev);
 	return sysfs_emit(buf, "%u\n", acpi_device_enumerated(adev));
 }
 static DEVICE_ATTR_RO(docked);

drivers/acpi/pci_link.c

@@ -606,12 +606,10 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 			       int *polarity, char **name)
 {
-	int result;
-	struct acpi_device *device;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_pci_link *link;
 
-	result = acpi_bus_get_device(handle, &device);
-	if (result) {
+	if (!device) {
 		acpi_handle_err(handle, "Invalid link device\n");
 		return -1;
 	}
@@ -658,12 +656,10 @@ int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
  */
 int acpi_pci_link_free_irq(acpi_handle handle)
 {
-	struct acpi_device *device;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_pci_link *link;
-	acpi_status result;
 
-	result = acpi_bus_get_device(handle, &device);
-	if (result) {
+	if (!device) {
 		acpi_handle_err(handle, "Invalid link device\n");
 		return -1;
 	}

drivers/acpi/pci_root.c

@@ -67,11 +67,10 @@ static struct acpi_scan_handler pci_root_handler = {
  */
 int acpi_is_root_bridge(acpi_handle handle)
 {
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	int ret;
-	struct acpi_device *device;
 
-	ret = acpi_bus_get_device(handle, &device);
-	if (ret)
+	if (!device)
 		return 0;
 
 	ret = acpi_match_device_ids(device, root_device_ids);
@@ -215,11 +214,10 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 {
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_pci_root *root;
-	struct acpi_device *device;
 
-	if (acpi_bus_get_device(handle, &device) ||
-	    acpi_match_device_ids(device, root_device_ids))
+	if (!device || acpi_match_device_ids(device, root_device_ids))
 		return NULL;
 
 	root = acpi_driver_data(device);
@@ -324,7 +322,7 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
  * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
  * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
  * @mask: Mask of _OSC bits to request control of, place to store control mask.
- * @req: Mask of _OSC bits the control of is essential to the caller.
+ * @support: _OSC supported capability.
  *
  * Run _OSC query for @mask and if that is successful, compare the returned
  * mask of control bits with @req.  If all of the @req bits are set in the

drivers/acpi/power.c

@@ -81,9 +81,9 @@ struct acpi_power_resource *to_power_resource(struct acpi_device *device)
 
 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
 {
-	struct acpi_device *device;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 
-	if (acpi_bus_get_device(handle, &device))
+	if (!device)
 		return NULL;
 
 	return to_power_resource(device);
@@ -716,6 +716,9 @@ int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 
 	mutex_lock(&acpi_device_lock);
 
+	dev_dbg(&dev->dev, "Enabling wakeup power (count %d)\n",
+		dev->wakeup.prepare_count);
+
 	if (dev->wakeup.prepare_count++)
 		goto out;
 
@@ -734,8 +737,11 @@ int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 	if (err) {
 		acpi_power_off_list(&dev->wakeup.resources);
 		dev->wakeup.prepare_count = 0;
+		goto out;
 	}
 
+	dev_dbg(&dev->dev, "Wakeup power enabled\n");
+
  out:
 	mutex_unlock(&acpi_device_lock);
 	return err;
@@ -757,6 +763,9 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 
 	mutex_lock(&acpi_device_lock);
 
+	dev_dbg(&dev->dev, "Disabling wakeup power (count %d)\n",
+		dev->wakeup.prepare_count);
+
 	/* Do nothing if wakeup power has not been enabled for this device. */
 	if (dev->wakeup.prepare_count <= 0)
 		goto out;
@@ -782,8 +791,11 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 	if (err) {
 		dev_err(&dev->dev, "Cannot turn off wakeup power resources\n");
 		dev->wakeup.flags.valid = 0;
+		goto out;
 	}
 
+	dev_dbg(&dev->dev, "Wakeup power disabled\n");
+
  out:
 	mutex_unlock(&acpi_device_lock);
 	return err;
@@ -916,15 +928,14 @@ static void acpi_power_add_resource_to_list(struct acpi_power_resource *resource
 
 struct acpi_device *acpi_add_power_resource(acpi_handle handle)
 {
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_power_resource *resource;
-	struct acpi_device *device = NULL;
 	union acpi_object acpi_object;
 	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 	acpi_status status;
 	u8 state_dummy;
 	int result;
 
-	acpi_bus_get_device(handle, &device);
 	if (device)
 		return device;
 

drivers/acpi/processor_driver.c

@@ -98,8 +98,13 @@ static int acpi_soft_cpu_online(unsigned int cpu)
 	struct acpi_processor *pr = per_cpu(processors, cpu);
 	struct acpi_device *device;
 
-	if (!pr || acpi_bus_get_device(pr->handle, &device))
+	if (!pr)
+		return 0;
+
+	device = acpi_fetch_acpi_dev(pr->handle);
+	if (!device)
 		return 0;
+
 	/*
 	 * CPU got physically hotplugged and onlined for the first time:
 	 * Initialize missing things.
@@ -125,9 +130,8 @@ static int acpi_soft_cpu_online(unsigned int cpu)
 static int acpi_soft_cpu_dead(unsigned int cpu)
 {
 	struct acpi_processor *pr = per_cpu(processors, cpu);
-	struct acpi_device *device;
 
-	if (!pr || acpi_bus_get_device(pr->handle, &device))
+	if (!pr || !acpi_fetch_acpi_dev(pr->handle))
 		return 0;
 
 	acpi_processor_reevaluate_tstate(pr, true);

drivers/acpi/processor_idle.c

@@ -1101,7 +1101,7 @@ static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
 
 	status = acpi_get_parent(handle, &pr_ahandle);
 	while (ACPI_SUCCESS(status)) {
-		acpi_bus_get_device(pr_ahandle, &d);
+		d = acpi_fetch_acpi_dev(pr_ahandle);
 		handle = pr_ahandle;
 
 		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))

drivers/acpi/property.c

@@ -687,9 +687,9 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
 		if (index)
 			return -EINVAL;
 
-		ret = acpi_bus_get_device(obj->reference.handle, &device);
-		if (ret)
-			return ret == -ENODEV ? -EINVAL : ret;
+		device = acpi_fetch_acpi_dev(obj->reference.handle);
+		if (!device)
+			return -EINVAL;
 
 		args->fwnode = acpi_fwnode_handle(device);
 		args->nargs = 0;
@@ -719,9 +719,8 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
 		if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
 			struct fwnode_handle *ref_fwnode;
 
-			ret = acpi_bus_get_device(element->reference.handle,
-						  &device);
-			if (ret)
+			device = acpi_fetch_acpi_dev(element->reference.handle);
+			if (!device)
 				return -EINVAL;
 
 			nargs = 0;

drivers/acpi/resource.c

@@ -791,9 +791,9 @@ static acpi_status acpi_res_consumer_cb(acpi_handle handle, u32 depth,
 {
 	struct resource *res = context;
 	struct acpi_device **consumer = (struct acpi_device **) ret;
-	struct acpi_device *adev;
+	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
 
-	if (acpi_bus_get_device(handle, &adev))
+	if (!adev)
 		return AE_OK;
 
 	if (acpi_dev_consumes_res(adev, res)) {

drivers/acpi/scan.c

@@ -135,12 +135,12 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
 static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
 				    void **ret_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_device_physical_node *pn;
 	bool second_pass = (bool)data;
 	acpi_status status = AE_OK;
 
-	if (acpi_bus_get_device(handle, &device))
+	if (!device)
 		return AE_OK;
 
 	if (device->handler && !device->handler->hotplug.enabled) {
@@ -180,10 +180,10 @@ static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
 static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,
 				   void **ret_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_device_physical_node *pn;
 
-	if (acpi_bus_get_device(handle, &device))
+	if (!device)
 		return AE_OK;
 
 	mutex_lock(&device->physical_node_lock);
@@ -599,6 +599,19 @@ int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
 }
 EXPORT_SYMBOL(acpi_bus_get_device);
 
+/**
+ * acpi_fetch_acpi_dev - Retrieve ACPI device object.
+ * @handle: ACPI handle associated with the requested ACPI device object.
+ *
+ * Return a pointer to the ACPI device object associated with @handle, if
+ * present, or NULL otherwise.
+ */
+struct acpi_device *acpi_fetch_acpi_dev(acpi_handle handle)
+{
+	return handle_to_device(handle, NULL);
+}
+EXPORT_SYMBOL_GPL(acpi_fetch_acpi_dev);
+
 static void get_acpi_device(void *dev)
 {
 	acpi_dev_get(dev);
@@ -799,7 +812,7 @@ static const char * const acpi_ignore_dep_ids[] = {
 
 static struct acpi_device *acpi_bus_get_parent(acpi_handle handle)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device;
 	acpi_status status;
 
 	/*
@@ -814,7 +827,9 @@ static struct acpi_device *acpi_bus_get_parent(acpi_handle handle)
 		status = acpi_get_parent(handle, &handle);
 		if (ACPI_FAILURE(status))
 			return status == AE_NULL_ENTRY ? NULL : acpi_root;
-	} while (acpi_bus_get_device(handle, &device));
+
+		device = acpi_fetch_acpi_dev(handle);
+	} while (!device);
 	return device;
 }
 
@@ -1340,12 +1355,12 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp,
 		if (info->valid & ACPI_VALID_HID) {
 			acpi_add_id(pnp, info->hardware_id.string);
 			pnp->type.platform_id = 1;
-		}
 			if (info->valid & ACPI_VALID_CID) {
 				cid_list = &info->compatible_id_list;
 				for (i = 0; i < cid_list->count; i++)
 					acpi_add_id(pnp, cid_list->ids[i].string);
 			}
+		}
 		if (info->valid & ACPI_VALID_ADR) {
 			pnp->bus_address = info->address;
 			pnp->type.bus_address = 1;
@@ -1695,6 +1710,7 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
 {
 	struct list_head resource_list;
 	bool is_serial_bus_slave = false;
+	static const struct acpi_device_id ignore_serial_bus_ids[] = {
 	/*
 	 * These devices have multiple I2cSerialBus resources and an i2c-client
 	 * must be instantiated for each, each with its own i2c_device_id.
@@ -1703,11 +1719,18 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
 	 * drivers/platform/x86/i2c-multi-instantiate.c driver, which knows
 	 * which i2c_device_id to use for each resource.
 	 */
-	static const struct acpi_device_id i2c_multi_instantiate_ids[] = {
 		{"BSG1160", },
 		{"BSG2150", },
 		{"INT33FE", },
 		{"INT3515", },
+	/*
+	 * HIDs of device with an UartSerialBusV2 resource for which userspace
+	 * expects a regular tty cdev to be created (instead of the in kernel
+	 * serdev) and which have a kernel driver which expects a platform_dev
+	 * such as the rfkill-gpio driver.
+	 */
+		{"BCM4752", },
+		{"LNV4752", },
 		{}
 	};
 
@@ -1721,8 +1744,7 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
 	     fwnode_property_present(&device->fwnode, "baud")))
 		return true;
 
-	/* Instantiate a pdev for the i2c-multi-instantiate drv to bind to */
-	if (!acpi_match_device_ids(device, i2c_multi_instantiate_ids))
+	if (!acpi_match_device_ids(device, ignore_serial_bus_ids))
 		return false;
 
 	INIT_LIST_HEAD(&resource_list);
@@ -2003,11 +2025,10 @@ static bool acpi_bus_scan_second_pass;
 static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
 				      struct acpi_device **adev_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	acpi_object_type acpi_type;
 	int type;
 
-	acpi_bus_get_device(handle, &device);
 	if (device)
 		goto out;
 
@@ -2548,8 +2569,8 @@ int __init acpi_scan_init(void)
 	if (result)
 		goto out;
 
-	result = acpi_bus_get_device(ACPI_ROOT_OBJECT, &acpi_root);
-	if (result)
+	acpi_root = acpi_fetch_acpi_dev(ACPI_ROOT_OBJECT);
+	if (!acpi_root)
 		goto out;
 
 	/* Fixed feature devices do not exist on HW-reduced platform */

drivers/acpi/sleep.c

@@ -73,7 +73,6 @@ static int acpi_sleep_prepare(u32 acpi_state)
 		acpi_set_waking_vector(acpi_wakeup_address);
 
 	}
-	ACPI_FLUSH_CPU_CACHE();
 #endif
 	pr_info("Preparing to enter system sleep state S%d\n", acpi_state);
 	acpi_enable_wakeup_devices(acpi_state);
@@ -566,8 +565,6 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	u32 acpi_state = acpi_target_sleep_state;
 	int error;
 
-	ACPI_FLUSH_CPU_CACHE();
-
 	trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true);
 	switch (acpi_state) {
 	case ACPI_STATE_S1:
@@ -903,8 +900,6 @@ static int acpi_hibernation_enter(void)
 {
 	acpi_status status = AE_OK;
 
-	ACPI_FLUSH_CPU_CACHE();
-
 	/* This shouldn't return.  If it returns, we have a problem */
 	status = acpi_enter_sleep_state(ACPI_STATE_S4);
 	/* Reprogram control registers */

drivers/acpi/thermal.c

@@ -697,7 +697,6 @@ static int acpi_thermal_cooling_device_cb(struct thermal_zone_device *thermal,
 	struct acpi_device *device = cdev->devdata;
 	struct acpi_thermal *tz = thermal->devdata;
 	struct acpi_device *dev;
-	acpi_status status;
 	acpi_handle handle;
 	int i;
 	int j;
@@ -715,8 +714,8 @@ static int acpi_thermal_cooling_device_cb(struct thermal_zone_device *thermal,
 		for (i = 0; i < tz->trips.passive.devices.count;
 		    i++) {
 			handle = tz->trips.passive.devices.handles[i];
-			status = acpi_bus_get_device(handle, &dev);
-			if (ACPI_FAILURE(status) || dev != device)
+			dev = acpi_fetch_acpi_dev(handle);
+			if (dev != device)
 				continue;
 			if (bind)
 				result =
@@ -741,8 +740,8 @@ static int acpi_thermal_cooling_device_cb(struct thermal_zone_device *thermal,
 		    j < tz->trips.active[i].devices.count;
 		    j++) {
 			handle = tz->trips.active[i].devices.handles[j];
-			status = acpi_bus_get_device(handle, &dev);
-			if (ACPI_FAILURE(status) || dev != device)
+			dev = acpi_fetch_acpi_dev(handle);
+			if (dev != device)
 				continue;
 			if (bind)
 				result = thermal_zone_bind_cooling_device

drivers/acpi/video_detect.c

@@ -59,18 +59,16 @@ static void acpi_video_parse_cmdline(void)
 static acpi_status
 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 {
+	struct acpi_device *acpi_dev = acpi_fetch_acpi_dev(handle);
 	long *cap = context;
 	struct pci_dev *dev;
-	struct acpi_device *acpi_dev;
 
 	static const struct acpi_device_id video_ids[] = {
 		{ACPI_VIDEO_HID, 0},
 		{"", 0},
 	};
-	if (acpi_bus_get_device(handle, &acpi_dev))
-		return AE_OK;
 
-	if (!acpi_match_device_ids(acpi_dev, video_ids)) {
+	if (acpi_dev && !acpi_match_device_ids(acpi_dev, video_ids)) {
 		dev = acpi_get_pci_dev(handle);
 		if (!dev)
 			return AE_OK;

drivers/acpi/x86/s2idle.c

@@ -293,9 +293,9 @@ static void lpi_check_constraints(void)
 
 	for (i = 0; i < lpi_constraints_table_size; ++i) {
 		acpi_handle handle = lpi_constraints_table[i].handle;
-		struct acpi_device *adev;
+		struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
 
-		if (!handle || acpi_bus_get_device(handle, &adev))
+		if (!adev)
 			continue;
 
 		acpi_handle_debug(handle,

drivers/acpi/x86/utils.c

@@ -10,6 +10,7 @@
 
 #include <linux/acpi.h>
 #include <linux/dmi.h>
+#include <linux/platform_device.h>
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
 #include "../internal.h"
@@ -160,3 +161,113 @@ bool force_storage_d3(void)
 {
 	return x86_match_cpu(storage_d3_cpu_ids);
 }
+
+#if IS_ENABLED(CONFIG_X86_ANDROID_TABLETS)
+/*
+ * x86 ACPI boards which ship with only Android as their factory image usually
+ * declare a whole bunch of bogus I2C devices in their ACPI tables and sometimes
+ * there are issues with serdev devices on these boards too, e.g. the resource
+ * points to the wrong serdev_controller.
+ *
+ * Instantiating I2C / serdev devs for these bogus devs causes various issues,
+ * e.g. GPIO/IRQ resource conflicts because sometimes drivers do bind to them.
+ * The Android x86 kernel fork shipped on these devices has some special code
+ * to remove the bogus I2C clients (and AFAICT serdevs are ignored completely).
+ *
+ * The acpi_quirk_skip_*_enumeration() functions below are used by the I2C or
+ * serdev code to skip instantiating any I2C or serdev devs on broken boards.
+ *
+ * In case of I2C an exception is made for HIDs on the i2c_acpi_known_good_ids
+ * list. These are known to always be correct (and in case of the audio-codecs
+ * the drivers heavily rely on the codec being enumerated through ACPI).
+ *
+ * Note these boards typically do actually have I2C and serdev devices,
+ * just different ones then the ones described in their DSDT. The devices
+ * which are actually present are manually instantiated by the
+ * drivers/platform/x86/x86-android-tablets.c kernel module.
+ */
+#define ACPI_QUIRK_SKIP_I2C_CLIENTS				BIT(0)
+#define ACPI_QUIRK_UART1_TTY_UART2_SKIP				BIT(1)
+
+static const struct dmi_system_id acpi_skip_serial_bus_enumeration_ids[] = {
+	{
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "ME176C"),
+		},
+		.driver_data = (void *)(ACPI_QUIRK_SKIP_I2C_CLIENTS |
+					ACPI_QUIRK_UART1_TTY_UART2_SKIP),
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TF103C"),
+		},
+		.driver_data = (void *)ACPI_QUIRK_SKIP_I2C_CLIENTS,
+	},
+	{
+		/* Whitelabel (sold as various brands) TM800A550L */
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "AMI Corporation"),
+			DMI_MATCH(DMI_BOARD_NAME, "Aptio CRB"),
+			/* Above strings are too generic, also match on BIOS version */
+			DMI_MATCH(DMI_BIOS_VERSION, "ZY-8-BI-PX4S70VTR400-X423B-005-D"),
+		},
+		.driver_data = (void *)ACPI_QUIRK_SKIP_I2C_CLIENTS,
+	},
+	{}
+};
+
+static const struct acpi_device_id i2c_acpi_known_good_ids[] = {
+	{ "10EC5640", 0 }, /* RealTek ALC5640 audio codec */
+	{ "INT33F4", 0 },  /* X-Powers AXP288 PMIC */
+	{ "INT33FD", 0 },  /* Intel Crystal Cove PMIC */
+	{ "NPCE69A", 0 },  /* Asus Transformer keyboard dock */
+	{}
+};
+
+bool acpi_quirk_skip_i2c_client_enumeration(struct acpi_device *adev)
+{
+	const struct dmi_system_id *dmi_id;
+	long quirks;
+
+	dmi_id = dmi_first_match(acpi_skip_serial_bus_enumeration_ids);
+	if (!dmi_id)
+		return false;
+
+	quirks = (unsigned long)dmi_id->driver_data;
+	if (!(quirks & ACPI_QUIRK_SKIP_I2C_CLIENTS))
+		return false;
+
+	return acpi_match_device_ids(adev, i2c_acpi_known_good_ids);
+}
+EXPORT_SYMBOL_GPL(acpi_quirk_skip_i2c_client_enumeration);
+
+int acpi_quirk_skip_serdev_enumeration(struct device *controller_parent, bool *skip)
+{
+	struct acpi_device *adev = ACPI_COMPANION(controller_parent);
+	const struct dmi_system_id *dmi_id;
+	long quirks = 0;
+
+	*skip = false;
+
+	/* !dev_is_platform() to not match on PNP enumerated debug UARTs */
+	if (!adev || !adev->pnp.unique_id || !dev_is_platform(controller_parent))
+		return 0;
+
+	dmi_id = dmi_first_match(acpi_skip_serial_bus_enumeration_ids);
+	if (dmi_id)
+		quirks = (unsigned long)dmi_id->driver_data;
+
+	if (quirks & ACPI_QUIRK_UART1_TTY_UART2_SKIP) {
+		if (!strcmp(adev->pnp.unique_id, "1"))
+			return -ENODEV; /* Create tty cdev instead of serdev */
+
+		if (!strcmp(adev->pnp.unique_id, "2"))
+			*skip = true;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_quirk_skip_serdev_enumeration);
+#endif

drivers/i2c/i2c-core-acpi.c

@@ -254,6 +254,13 @@ static void i2c_acpi_register_device(struct i2c_adapter *adapter,
 				     struct acpi_device *adev,
 				     struct i2c_board_info *info)
 {
+	/*
+	 * Skip registration on boards where the ACPI tables are
+	 * known to contain bogus I2C devices.
+	 */
+	if (acpi_quirk_skip_i2c_client_enumeration(adev))
+		return;
+
 	adev->power.flags.ignore_parent = true;
 	acpi_device_set_enumerated(adev);
 

drivers/tty/serdev/core.c

@@ -727,10 +727,24 @@ static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 {
 	acpi_status status;
+	bool skip;
+	int ret;
 
 	if (!has_acpi_companion(ctrl->dev.parent))
 		return -ENODEV;
 
+	/*
+	 * Skip registration on boards where the ACPI tables are known to
+	 * contain buggy devices. Note serdev_controller_add() must still
+	 * succeed in this case, so that the proper serdev devices can be
+	 * added "manually" later.
+	 */
+	ret = acpi_quirk_skip_serdev_enumeration(ctrl->dev.parent, &skip);
+	if (ret)
+		return ret;
+	if (skip)
+		return 0;
+
 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 				     SERDEV_ACPI_MAX_SCAN_DEPTH,
 				     acpi_serdev_add_device, NULL, ctrl, NULL);

include/acpi/acpi_bus.h

@@ -505,6 +505,7 @@ extern int unregister_acpi_notifier(struct notifier_block *);
  */
 
 int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device);
+struct acpi_device *acpi_fetch_acpi_dev(acpi_handle handle);
 acpi_status acpi_bus_get_status_handle(acpi_handle handle,
 				       unsigned long long *sta);
 int acpi_bus_get_status(struct acpi_device *device);
@@ -621,6 +622,22 @@ static inline bool acpi_device_always_present(struct acpi_device *adev)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_X86_ANDROID_TABLETS)
+bool acpi_quirk_skip_i2c_client_enumeration(struct acpi_device *adev);
+int acpi_quirk_skip_serdev_enumeration(struct device *controller_parent, bool *skip);
+#else
+static inline bool acpi_quirk_skip_i2c_client_enumeration(struct acpi_device *adev)
+{
+	return false;
+}
+static inline int
+acpi_quirk_skip_serdev_enumeration(struct device *controller_parent, bool *skip)
+{
+	*skip = false;
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_PM
 void acpi_pm_wakeup_event(struct device *dev);
 acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,