ACPI 5.0 introduces _DEP 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 the 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. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=69011 Tested-by: Jan-Michael Brummer <jan.brum...@tabos.org> Tested-by: Adam Williamson <ad...@happyassassin.net> Tested-by: Michael Shigorin <shigo...@gmail.com> Acked-by: Wolfram Sang <w...@the-dreams.de> Acked-by: Mika Westerberg <mika.westerb...@linux.intel.com> Signed-off-by: Lan Tianyu <tianyu....@intel.com> --- Change since V2: Coding style change Change since V1: Remove redundant blank line and some coding style fixs. drivers/acpi/battery.c | 4 +++ drivers/acpi/scan.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/i2c/i2c-core.c | 1 + include/acpi/acpi_bus.h | 1 + include/linux/acpi.h | 1 + 5 files changed, 92 insertions(+) diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index 8ec8a89..d98ba43 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -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; diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 9cb5cca..1b1cf55 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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; @@ -2193,6 +2201,59 @@ 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) { @@ -2219,6 +2280,7 @@ 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) @@ -2339,6 +2401,29 @@ 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. diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index f43b4e1..68aeb8e 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -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; } diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index 7d1ce40..d539084 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -372,6 +372,7 @@ 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 *); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 10f2ed9..e09f7f4 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -428,6 +428,7 @@ extern bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv); 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) -- 1.8.4.rc0.1.g8f6a3e5.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
