workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 822 insertions, 0 deletions

diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
new file mode 100644
index 000000000..3836ee75d
--- /dev/null
+++ b/drivers/acpi/button.c
@@ -0,0 +1,822 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  button.c - ACPI Button Driver
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ */
+
+#define pr_fmt(fmt) "ACPI: button: " fmt
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <linux/platform_device.h>
+#include <acpi/button.h>
+
+#define ACPI_BUTTON_CLASS		"button"
+#define ACPI_BUTTON_FILE_STATE		"state"
+#define ACPI_BUTTON_TYPE_UNKNOWN	0x00
+#define ACPI_BUTTON_NOTIFY_WAKE		0x02
+#define ACPI_BUTTON_NOTIFY_STATUS	0x80
+
+#define ACPI_BUTTON_CLASS_POWER		"button/power"
+#define ACPI_BUTTON_DEVICE_NAME_POWER	"Power Button"
+#define ACPI_BUTTON_TYPE_POWER		0x01
+
+#define ACPI_BUTTON_CLASS_SLEEP		"button/sleep"
+#define ACPI_BUTTON_DEVICE_NAME_SLEEP	"Sleep Button"
+#define ACPI_BUTTON_TYPE_SLEEP		0x03
+
+#define ACPI_BUTTON_CLASS_LID		"button/lid"
+#define ACPI_BUTTON_SUBCLASS_LID	"lid"
+#define ACPI_BUTTON_DEVICE_NAME_LID	"Lid Switch"
+#define ACPI_BUTTON_TYPE_LID		0x05
+
+enum {
+	ACPI_BUTTON_LID_INIT_IGNORE,
+	ACPI_BUTTON_LID_INIT_OPEN,
+	ACPI_BUTTON_LID_INIT_METHOD,
+	ACPI_BUTTON_LID_INIT_DISABLED,
+};
+
+static const char * const lid_init_state_str[] = {
+	[ACPI_BUTTON_LID_INIT_IGNORE]		= "ignore",
+	[ACPI_BUTTON_LID_INIT_OPEN]		= "open",
+	[ACPI_BUTTON_LID_INIT_METHOD]		= "method",
+	[ACPI_BUTTON_LID_INIT_DISABLED]		= "disabled",
+};
+
+MODULE_AUTHOR("Paul Diefenbaugh");
+MODULE_DESCRIPTION("ACPI Button Driver");
+MODULE_LICENSE("GPL");
+
+static const struct acpi_device_id button_device_ids[] = {
+	{ACPI_BUTTON_HID_LID, ACPI_BUTTON_TYPE_LID},
+	{ACPI_BUTTON_HID_SLEEP, ACPI_BUTTON_TYPE_SLEEP},
+	{ACPI_BUTTON_HID_SLEEPF, ACPI_BUTTON_TYPE_SLEEP},
+	{ACPI_BUTTON_HID_POWER, ACPI_BUTTON_TYPE_POWER},
+	{ACPI_BUTTON_HID_POWERF, ACPI_BUTTON_TYPE_POWER},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, button_device_ids);
+
+/* Please keep this list sorted alphabetically by vendor and model */
+static const struct dmi_system_id dmi_lid_quirks[] = {
+	{
+		/* GP-electronic T701, _LID method points to a floating GPIO */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
+			DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+	},
+	{
+		/* Nextbook Ares 8A tablet, _LID device always reports lid closed */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CherryTrail"),
+			DMI_MATCH(DMI_BIOS_VERSION, "M882"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+	},
+	{
+		/*
+		 * Lenovo Yoga 9 14ITL5, initial notification of the LID device
+		 * never happens.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "82BG"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Medion Akoya E2215T, notification of the LID device only
+		 * happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "E2215T"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Medion Akoya E2228T, notification of the LID device only
+		 * happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "E2228T"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Razer Blade Stealth 13 late 2019, notification of the LID device
+		 * only happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Samsung galaxybook2 ,initial _LID device notification returns
+		 * lid closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "750XED"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{}
+};
+
+static int acpi_button_probe(struct platform_device *pdev);
+static void acpi_button_remove(struct platform_device *pdev);
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev);
+static int acpi_button_resume(struct device *dev);
+#else
+#define acpi_button_suspend NULL
+#define acpi_button_resume NULL
+#endif
+static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
+
+static struct platform_driver acpi_button_driver = {
+	.probe = acpi_button_probe,
+	.remove = acpi_button_remove,
+	.driver = {
+		.name = "acpi-button",
+		.acpi_match_table = button_device_ids,
+		.pm = &acpi_button_pm,
+	},
+};
+
+struct acpi_button {
+	struct acpi_device *adev;
+	struct device *dev;		/* physical button device */
+	unsigned int type;
+	struct input_dev *input;
+	const char *class;		/* for netlink messages */
+	char phys[32];			/* for input device */
+	unsigned long pushed;
+	bool last_state;
+	ktime_t last_time;
+	bool suspended;
+	bool lid_state_initialized;
+	bool gpe_enabled;
+};
+
+static long lid_init_state = -1;
+
+static unsigned long lid_report_interval __read_mostly = 500;
+module_param(lid_report_interval, ulong, 0644);
+MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
+
+/* FS Interface (/proc) */
+static struct proc_dir_entry *acpi_button_dir;
+static struct proc_dir_entry *acpi_lid_dir;
+
+static int acpi_lid_evaluate_state(acpi_handle lid_handle)
+{
+	unsigned long long lid_state;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(lid_handle, "_LID", NULL, &lid_state);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return !!lid_state;
+}
+
+static void acpi_lid_notify_state(struct acpi_button *button, bool state)
+{
+	struct acpi_device *device = button->adev;
+	ktime_t next_report;
+	bool do_update;
+
+	/*
+	 * In lid_init_state=ignore mode, if user opens/closes lid
+	 * frequently with "open" missing, and "last_time" is also updated
+	 * frequently, "close" cannot be delivered to the userspace.
+	 * So "last_time" is only updated after a timeout or an actual
+	 * switch.
+	 */
+	do_update = lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
+			button->last_state != state;
+	next_report = ktime_add(button->last_time,
+				ms_to_ktime(lid_report_interval));
+	if (button->last_state == state &&
+	    ktime_after(ktime_get(), next_report)) {
+		/* Complain about the buggy firmware. */
+		pr_warn_once(FW_BUG "Unexpected lid state reported by firmware\n");
+
+		/*
+		 * Send the unreliable complement switch event:
+		 *
+		 * On most platforms, the lid device is reliable. However
+		 * there are exceptions:
+		 * 1. Platforms returning initial lid state as "close" by
+		 *    default after booting/resuming:
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
+		 * 2. Platforms never reporting "open" events:
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
+		 * On these buggy platforms, the usage model of the ACPI
+		 * lid device actually is:
+		 * 1. The initial returning value of _LID may not be
+		 *    reliable.
+		 * 2. The open event may not be reliable.
+		 * 3. The close event is reliable.
+		 *
+		 * But SW_LID is typed as input switch event, the input
+		 * layer checks if the event is redundant. Hence if the
+		 * state is not switched, the userspace cannot see this
+		 * platform triggered reliable event. By inserting a
+		 * complement switch event, it then is guaranteed that the
+		 * platform triggered reliable one can always be seen by
+		 * the userspace.
+		 */
+		if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
+			do_update = true;
+			/*
+			 * Do generate complement switch event for "close"
+			 * as "close" is reliable and wrong "open" won't
+			 * trigger unexpected behaviors.
+			 * Do not generate complement switch event for
+			 * "open" as "open" is not reliable and wrong
+			 * "close" will trigger unexpected behaviors.
+			 */
+			if (!state) {
+				input_report_switch(button->input,
+						    SW_LID, state);
+				input_sync(button->input);
+			}
+		}
+	}
+	/* Send the platform triggered reliable event */
+	if (do_update) {
+		acpi_handle_debug(device->handle, "ACPI LID %s\n",
+				  state ? "open" : "closed");
+		input_report_switch(button->input, SW_LID, !state);
+		input_sync(button->input);
+		button->last_state = state;
+		button->last_time = ktime_get();
+	}
+}
+
+static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
+						     void *offset)
+{
+	struct acpi_button *button = seq->private;
+	int state;
+
+	state = acpi_lid_evaluate_state(button->adev->handle);
+	seq_printf(seq, "state:      %s\n",
+		   state < 0 ? "unsupported" : (state ? "open" : "closed"));
+	return 0;
+}
+
+static int acpi_lid_add_fs(struct acpi_button *button)
+{
+	struct acpi_device *device = button->adev;
+	struct proc_dir_entry *entry = NULL;
+
+	if (acpi_button_dir || acpi_lid_dir) {
+		pr_info("More than one Lid device found!\n");
+		return -EEXIST;
+	}
+
+	/* create /proc/acpi/button */
+	acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
+	if (!acpi_button_dir)
+		return -ENODEV;
+
+	/* create /proc/acpi/button/lid */
+	acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	if (!acpi_lid_dir)
+		goto remove_button_dir;
+
+	/* create /proc/acpi/button/lid/LID/ */
+	acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
+	if (!acpi_device_dir(device))
+		goto remove_lid_dir;
+
+	/* create /proc/acpi/button/lid/LID/state */
+	entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
+			acpi_device_dir(device), acpi_button_state_seq_show,
+			button);
+	if (!entry)
+		goto remove_dev_dir;
+
+	return 0;
+
+remove_dev_dir:
+	remove_proc_entry(acpi_device_bid(device), acpi_lid_dir);
+	acpi_device_dir(device) = NULL;
+remove_lid_dir:
+	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	acpi_lid_dir = NULL;
+remove_button_dir:
+	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+	acpi_button_dir = NULL;
+	return -ENODEV;
+}
+
+static void acpi_lid_remove_fs(void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+
+	remove_proc_entry(ACPI_BUTTON_FILE_STATE,
+			  acpi_device_dir(device));
+	remove_proc_entry(acpi_device_bid(device),
+			  acpi_lid_dir);
+	acpi_device_dir(device) = NULL;
+	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	acpi_lid_dir = NULL;
+	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+	acpi_button_dir = NULL;
+}
+
+static int devm_acpi_lid_add_fs(struct device *dev, struct acpi_button *button)
+{
+	int ret;
+
+	ret = acpi_lid_add_fs(button);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, acpi_lid_remove_fs, button);
+}
+
+static acpi_handle saved_lid_handle;
+static DEFINE_MUTEX(acpi_lid_lock);
+
+static void acpi_lid_save(struct acpi_device *adev)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	saved_lid_handle = adev->handle;
+}
+
+static void acpi_lid_forget(struct acpi_device *adev)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	if (saved_lid_handle == adev->handle)
+		saved_lid_handle = NULL;
+}
+
+/* Driver Interface */
+int acpi_lid_open(void)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	if (!saved_lid_handle)
+		return -ENODEV;
+
+	return acpi_lid_evaluate_state(saved_lid_handle);
+}
+EXPORT_SYMBOL(acpi_lid_open);
+
+static void acpi_lid_update_state(struct acpi_button *button, bool signal_wakeup)
+{
+	int state;
+
+	state = acpi_lid_evaluate_state(button->adev->handle);
+	if (state < 0)
+		return;
+
+	if (state && signal_wakeup)
+		acpi_pm_wakeup_event(button->dev);
+
+	acpi_lid_notify_state(button, state);
+}
+
+static void acpi_lid_initialize_state(struct acpi_button *button)
+{
+	switch (lid_init_state) {
+	case ACPI_BUTTON_LID_INIT_OPEN:
+		acpi_lid_notify_state(button, true);
+		break;
+	case ACPI_BUTTON_LID_INIT_METHOD:
+		acpi_lid_update_state(button, false);
+		break;
+	case ACPI_BUTTON_LID_INIT_IGNORE:
+	default:
+		break;
+	}
+
+	button->lid_state_initialized = true;
+}
+
+static void acpi_lid_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+
+	if (event != ACPI_BUTTON_NOTIFY_STATUS) {
+		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
+				  event);
+		return;
+	}
+
+	if (!button->lid_state_initialized)
+		return;
+
+	acpi_lid_update_state(button, true);
+}
+
+static void acpi_button_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+	struct input_dev *input;
+	int keycode;
+
+	switch (event) {
+	case ACPI_BUTTON_NOTIFY_STATUS:
+		break;
+	case ACPI_BUTTON_NOTIFY_WAKE:
+		break;
+	default:
+		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
+				  event);
+		return;
+	}
+
+	acpi_pm_wakeup_event(button->dev);
+
+	if (button->suspended || event == ACPI_BUTTON_NOTIFY_WAKE)
+		return;
+
+	input = button->input;
+	keycode = test_bit(KEY_SLEEP, input->keybit) ? KEY_SLEEP : KEY_POWER;
+
+	input_report_key(input, keycode, 1);
+	input_sync(input);
+	input_report_key(input, keycode, 0);
+	input_sync(input);
+
+	acpi_bus_generate_netlink_event(button->class, dev_name(&device->dev),
+					event, ++button->pushed);
+}
+
+static void acpi_button_notify_run(void *data)
+{
+	acpi_button_notify(NULL, ACPI_BUTTON_NOTIFY_STATUS, data);
+}
+
+static u32 acpi_button_event(void *data)
+{
+	acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_button_notify_run, data);
+	return ACPI_INTERRUPT_HANDLED;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev)
+{
+	struct acpi_button *button = dev_get_drvdata(dev);
+
+	button->suspended = true;
+	return 0;
+}
+
+static int acpi_button_resume(struct device *dev)
+{
+	struct acpi_button *button = dev_get_drvdata(dev);
+	struct input_dev *input;
+
+	button->suspended = false;
+	if (button->type == ACPI_BUTTON_TYPE_LID) {
+		button->last_state = !!acpi_lid_evaluate_state(ACPI_HANDLE(dev));
+		button->last_time = ktime_get();
+		acpi_lid_initialize_state(button);
+	}
+
+	if (button->type == ACPI_BUTTON_TYPE_POWER) {
+		input = button->input;
+		input_report_key(input, KEY_WAKEUP, 1);
+		input_sync(input);
+		input_report_key(input, KEY_WAKEUP, 0);
+		input_sync(input);
+	}
+	return 0;
+}
+#endif
+
+static int acpi_lid_input_open(struct input_dev *input)
+{
+	struct acpi_button *button = input_get_drvdata(input);
+
+	button->last_state = !!acpi_lid_evaluate_state(button->adev->handle);
+	button->last_time = ktime_get();
+	acpi_lid_initialize_state(button);
+
+	return 0;
+}
+
+static acpi_notify_handler acpi_button_notify_handler(struct acpi_button *button)
+{
+	if (button->type == ACPI_BUTTON_TYPE_LID)
+		return acpi_lid_notify;
+
+	return acpi_button_notify;
+}
+
+static void acpi_button_wakeup_cleanup(void *data)
+{
+	device_init_wakeup(data, false);
+}
+
+static int devm_acpi_button_init_wakeup(struct device *dev)
+{
+	device_init_wakeup(dev, true);
+	return devm_add_action_or_reset(dev, acpi_button_wakeup_cleanup, dev);
+}
+
+static void acpi_button_remove_event_handler(void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *adev = button->adev;
+
+	switch (adev->device_type) {
+	case ACPI_BUS_TYPE_POWER_BUTTON:
+		acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+						acpi_button_event);
+		break;
+
+	case ACPI_BUS_TYPE_SLEEP_BUTTON:
+		acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+						acpi_button_event);
+		break;
+
+	default:
+		if (button->gpe_enabled) {
+			dev_dbg(button->dev, "Disabling ACPI GPE%02llx\n",
+				adev->wakeup.gpe_number);
+			acpi_disable_gpe(adev->wakeup.gpe_device,
+					 adev->wakeup.gpe_number);
+		}
+		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
+					   acpi_button_notify_handler(button));
+		break;
+	}
+	acpi_os_wait_events_complete();
+}
+
+static int acpi_button_add_fixed_event_handler(u32 event,
+					       struct acpi_button *button)
+{
+	acpi_status status;
+
+	status = acpi_install_fixed_event_handler(event, acpi_button_event, button);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return 0;
+}
+
+static int acpi_button_add_event_handler(struct acpi_button *button)
+{
+	struct acpi_device *adev = button->adev;
+	acpi_status status;
+
+	if (adev->device_type == ACPI_BUS_TYPE_POWER_BUTTON)
+		return acpi_button_add_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+							   button);
+
+	if (adev->device_type == ACPI_BUS_TYPE_SLEEP_BUTTON)
+		return acpi_button_add_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+							   button);
+
+	status = acpi_install_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
+					     acpi_button_notify_handler(button),
+					     button);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	if (!adev->wakeup.flags.valid)
+		return 0;
+
+	/*
+	 * If the wakeup GPE has a handler method, enable it in case it is also
+	 * used for signaling runtime events.
+	 */
+	status = acpi_enable_gpe_cond(adev->wakeup.gpe_device,
+				      adev->wakeup.gpe_number,
+				      ACPI_GPE_DISPATCH_METHOD);
+	button->gpe_enabled = ACPI_SUCCESS(status);
+	if (button->gpe_enabled)
+		dev_dbg(button->dev, "Enabled ACPI GPE%02llx\n",
+			adev->wakeup.gpe_number);
+
+	return 0;
+}
+
+static int devm_acpi_button_add_event_handler(struct device *dev,
+					      struct acpi_button *button)
+{
+	int ret;
+
+	ret = acpi_button_add_event_handler(button);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, acpi_button_remove_event_handler,
+					button);
+}
+
+static int acpi_button_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct acpi_device *device = ACPI_COMPANION(dev);
+	const struct acpi_device_id *id;
+	struct acpi_button *button;
+	struct input_dev *input;
+	u8 button_type;
+	int error = 0;
+
+	id = acpi_match_acpi_device(button_device_ids, device);
+	if (!id || strcmp(acpi_device_hid(device), id->id))
+		return dev_err_probe(dev, -ENODEV, "Unsupported device\n");
+
+	button_type = id->driver_data;
+	if (button_type == ACPI_BUTTON_TYPE_LID &&
+	    lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
+		return -ENODEV;
+
+	button = devm_kzalloc(dev, sizeof(*button), GFP_KERNEL);
+	if (!button)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, button);
+
+	button->dev = dev;
+	button->adev = device;
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	button->input = input;
+	button->type = button_type;
+
+	switch (button_type) {
+	case ACPI_BUTTON_TYPE_LID:
+		button->class = ACPI_BUTTON_CLASS_LID;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_LID;
+		input_set_capability(input, EV_SW, SW_LID);
+		input->open = acpi_lid_input_open;
+
+		error = devm_acpi_lid_add_fs(dev, button);
+		if (error)
+			return error;
+
+		break;
+
+	case ACPI_BUTTON_TYPE_POWER:
+		button->class = ACPI_BUTTON_CLASS_POWER;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_POWER;
+		input_set_capability(input, EV_KEY, KEY_POWER);
+		input_set_capability(input, EV_KEY, KEY_WAKEUP);
+		break;
+
+	case ACPI_BUTTON_TYPE_SLEEP:
+		button->class = ACPI_BUTTON_CLASS_SLEEP;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_SLEEP;
+		input_set_capability(input, EV_KEY, KEY_SLEEP);
+		break;
+
+	default:
+		return dev_err_probe(dev, -ENODEV, "Unrecognized button type\n");
+	}
+
+	snprintf(button->phys, sizeof(button->phys), "%s/button/input0",
+		 acpi_device_hid(device));
+
+	input->phys = button->phys;
+	input->id.bustype = BUS_HOST;
+	input->id.product = button_type;
+
+	input_set_drvdata(input, button);
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	error = devm_acpi_button_init_wakeup(dev);
+	if (error)
+		return error;
+
+	error = devm_acpi_button_add_event_handler(dev, button);
+	if (error)
+		return error;
+
+	if (button_type == ACPI_BUTTON_TYPE_LID) {
+		/*
+		 * This assumes there's only one lid device, or if there are
+		 * more we only care about the last one...
+		 */
+		acpi_lid_save(device);
+	}
+
+	pr_info("%s [%s]\n", input->name, acpi_device_bid(device));
+
+	return 0;
+}
+
+static void acpi_button_remove(struct platform_device *pdev)
+{
+	struct acpi_button *button = platform_get_drvdata(pdev);
+
+	if (button->type == ACPI_BUTTON_TYPE_LID)
+		acpi_lid_forget(button->adev);
+}
+
+static int param_set_lid_init_state(const char *val,
+				    const struct kernel_param *kp)
+{
+	int i;
+
+	i = sysfs_match_string(lid_init_state_str, val);
+	if (i < 0)
+		return i;
+
+	lid_init_state = i;
+	pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
+	return 0;
+}
+
+static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
+{
+	int i, c = 0;
+
+	for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
+		if (i == lid_init_state)
+			c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
+		else
+			c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
+
+	buf[c - 1] = '\n'; /* Replace the final space with a newline */
+
+	return c;
+}
+
+module_param_call(lid_init_state,
+		  param_set_lid_init_state, param_get_lid_init_state,
+		  NULL, 0644);
+MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
+
+static int __init acpi_button_init(void)
+{
+	const struct dmi_system_id *dmi_id;
+
+	if (lid_init_state == -1) {
+		dmi_id = dmi_first_match(dmi_lid_quirks);
+		if (dmi_id)
+			lid_init_state = (long)dmi_id->driver_data;
+		else
+			lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
+	}
+
+	/*
+	 * Modules such as nouveau.ko and i915.ko have a link time dependency
+	 * on acpi_lid_open(), and would therefore not be loadable on ACPI
+	 * capable kernels booted in non-ACPI mode if the return value of
+	 * platform_driver_register() is returned from here with ACPI disabled
+	 * when this driver is built as a module.
+	 */
+	if (acpi_disabled)
+		return 0;
+
+	return platform_driver_register(&acpi_button_driver);
+}
+
+static void __exit acpi_button_exit(void)
+{
+	if (!acpi_disabled)
+		platform_driver_unregister(&acpi_button_driver);
+}
+
+module_init(acpi_button_init);
+module_exit(acpi_button_exit);