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Commit 40e7fcb1 authored by Lan Tianyu's avatar Lan Tianyu Committed by Rafael J. Wysocki
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ACPI: Add _DEP support to fix battery issue on Asus T100TA 

ACPI 5.0 introduces _DEP (Operation Region Dependencies) to designate
device objects that OSPM should assign a higher priority in start
ordering due to future operation region accesses.

On Asus T100TA, ACPI battery info are read from a I2C slave device via
I2C operation region. Before I2C operation region handler is installed,
battery _STA always returns 0. There is a _DEP method of designating
start order under battery device node.

This patch is to implement _DEP feature to fix battery issue on the
Asus T100TA.  Introducing acpi_dep_list and adding dep_unmet count
in struct acpi_device. During ACPI namespace scan, create struct
acpi_dep_data for a valid pair of master (device pointed to by _DEP)/
slave(device with _DEP), record master's and slave's ACPI handle in
it and put it into acpi_dep_list. The dep_unmet count will increase
by one if there is a device under its _DEP. Driver's probe() should
return EPROBE_DEFER when find dep_unmet is larger than 0. When I2C
operation region handler is installed, remove all struct acpi_dep_data
on the acpi_dep_list whose master is pointed to I2C host controller
and decrease slave's dep_unmet. When dep_unmet decreases to 0, all
_DEP conditions are met and then do acpi_bus_attach() for the device
in order to resolve battery _STA issue on the Asus T100TA.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=69011


Tested-by: default avatarJan-Michael Brummer <jan.brummer@tabos.org>
Tested-by: default avatarAdam Williamson <adamw@happyassassin.net>
Tested-by: default avatarMichael Shigorin <shigorin@gmail.com>
Acked-by: default avatarWolfram Sang <wsa@the-dreams.de>
Acked-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5d01410f

drivers/acpi/battery.c

+4 −0
Original line number Diff line number Diff line
@@ -1180,6 +1180,10 @@ static int acpi_battery_add(struct acpi_device *device) 


	if (!device)

		return -EINVAL;



	if (device->dep_unmet)

		return -EPROBE_DEFER;



	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);

	if (!battery)

		return -ENOMEM;

drivers/acpi/scan.c

+85 −0
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ bool acpi_force_hot_remove; 


static const char *dummy_hid = "device";



static LIST_HEAD(acpi_dep_list);

static DEFINE_MUTEX(acpi_dep_list_lock);

static LIST_HEAD(acpi_bus_id_list);

static DEFINE_MUTEX(acpi_scan_lock);

static LIST_HEAD(acpi_scan_handlers_list);
@@ -43,6 +45,12 @@ DEFINE_MUTEX(acpi_device_lock); 
LIST_HEAD(acpi_wakeup_device_list);

static DEFINE_MUTEX(acpi_hp_context_lock);



struct acpi_dep_data {

	struct list_head node;

	acpi_handle master;

	acpi_handle slave;

};



struct acpi_device_bus_id{

	char bus_id[15];

	unsigned int instance_no;
@@ -2086,6 +2094,59 @@ static void acpi_scan_init_hotplug(struct acpi_device *adev) 
	}

}



static void acpi_device_dep_initialize(struct acpi_device *adev)

{

	struct acpi_dep_data *dep;

	struct acpi_handle_list dep_devices;

	acpi_status status;

	int i;



	if (!acpi_has_method(adev->handle, "_DEP"))

		return;



	status = acpi_evaluate_reference(adev->handle, "_DEP", NULL,

					&dep_devices);

	if (ACPI_FAILURE(status)) {

		dev_err(&adev->dev, "Failed to evaluate _DEP.\n");

		return;

	}



	for (i = 0; i < dep_devices.count; i++) {

		struct acpi_device_info *info;

		int skip;



		status = acpi_get_object_info(dep_devices.handles[i], &info);

		if (ACPI_FAILURE(status)) {

			dev_err(&adev->dev, "Error reading device info\n");

			continue;

		}



		/*

		 * Skip the dependency of Windows System Power

		 * Management Controller

		 */

		skip = info->valid & ACPI_VALID_HID &&

			!strcmp(info->hardware_id.string, "INT3396");



		kfree(info);



		if (skip)

			continue;



		dep = kzalloc(sizeof(struct acpi_dep_data), GFP_KERNEL);

		if (!dep)

			return;



		dep->master = dep_devices.handles[i];

		dep->slave  = adev->handle;

		adev->dep_unmet++;



		mutex_lock(&acpi_dep_list_lock);

		list_add_tail(&dep->node , &acpi_dep_list);

		mutex_unlock(&acpi_dep_list_lock);

	}

}



static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,

				      void *not_used, void **return_value)

{
@@ -2112,6 +2173,7 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used, 
		return AE_CTRL_DEPTH;



	acpi_scan_init_hotplug(device);

	acpi_device_dep_initialize(device);



 out:

	if (!*return_value)
@@ -2232,6 +2294,29 @@ static void acpi_bus_attach(struct acpi_device *device) 
		device->handler->hotplug.notify_online(device);

}



void acpi_walk_dep_device_list(acpi_handle handle)

{

	struct acpi_dep_data *dep, *tmp;

	struct acpi_device *adev;



	mutex_lock(&acpi_dep_list_lock);

	list_for_each_entry_safe(dep, tmp, &acpi_dep_list, node) {

		if (dep->master == handle) {

			acpi_bus_get_device(dep->slave, &adev);

			if (!adev)

				continue;



			adev->dep_unmet--;

			if (!adev->dep_unmet)

				acpi_bus_attach(adev);

			list_del(&dep->node);

			kfree(dep);

		}

	}

	mutex_unlock(&acpi_dep_list_lock);

}

EXPORT_SYMBOL_GPL(acpi_walk_dep_device_list);



/**

 * acpi_bus_scan - Add ACPI device node objects in a given namespace scope.

 * @handle: Root of the namespace scope to scan.

drivers/i2c/i2c-core.c

+1 −0
Original line number Diff line number Diff line
@@ -403,6 +403,7 @@ static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) 
		return -ENOMEM;

	}



	acpi_walk_dep_device_list(handle);

	return 0;

}

include/acpi/acpi_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -359,6 +359,7 @@ struct acpi_device { 
	void *driver_data;

	struct device dev;

	unsigned int physical_node_count;

	unsigned int dep_unmet;

	struct list_head physical_node_list;

	struct mutex physical_node_lock;

	void (*remove)(struct acpi_device *);

include/linux/acpi.h

+1 −0
Original line number Diff line number Diff line
@@ -431,6 +431,7 @@ static inline bool acpi_driver_match_device(struct device *dev, 


int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *);

int acpi_device_modalias(struct device *, char *, int);

void acpi_walk_dep_device_list(acpi_handle handle);



struct platform_device *acpi_create_platform_device(struct acpi_device *);

#define ACPI_PTR(_ptr)	(_ptr)