diff --git a/Documentation/wmi/devices/dell-wmi-ddv.rst b/Documentation/wmi/devices/dell-wmi-ddv.rst index e0c20af30948..f10a623acca1 100644 --- a/Documentation/wmi/devices/dell-wmi-ddv.rst +++ b/Documentation/wmi/devices/dell-wmi-ddv.rst @@ -260,14 +260,6 @@ Some machines like the Dell Inspiron 3505 only support a single battery and thus ignore the battery index. Because of this the driver depends on the ACPI battery hook mechanism to discover batteries. -.. note:: - The ACPI battery matching algorithm currently used inside the driver is - outdated and does not match the algorithm described above. The reasons for - this are differences in the handling of the ToHexString() ACPI opcode between - Linux and Windows, which distorts the serial number of ACPI batteries on many - machines. Until this issue is resolved, the driver cannot use the above - algorithm. - Reverse-Engineering the DDV WMI interface ========================================= diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c index f27739da380f..711639001be4 100644 --- a/drivers/platform/x86/dell/dell-wmi-ddv.c +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c @@ -39,6 +39,9 @@ #define DELL_DDV_SUPPORTED_VERSION_MAX 3 #define DELL_DDV_GUID "8A42EA14-4F2A-FD45-6422-0087F7A7E608" +/* Battery indices 1, 2 and 3 */ +#define DELL_DDV_NUM_BATTERIES 3 + #define DELL_EPPID_LENGTH 20 #define DELL_EPPID_EXT_LENGTH 23 @@ -105,6 +108,8 @@ struct dell_wmi_ddv_sensors { struct dell_wmi_ddv_data { struct acpi_battery_hook hook; struct device_attribute eppid_attr; + struct mutex translation_cache_lock; /* Protects the translation cache */ + struct power_supply *translation_cache[DELL_DDV_NUM_BATTERIES]; struct dell_wmi_ddv_sensors fans; struct dell_wmi_ddv_sensors temps; struct wmi_device *wdev; @@ -639,15 +644,78 @@ static int dell_wmi_ddv_hwmon_add(struct dell_wmi_ddv_data *data) return ret; } -static int dell_wmi_ddv_battery_index(struct acpi_device *acpi_dev, u32 *index) +static int dell_wmi_ddv_battery_translate(struct dell_wmi_ddv_data *data, + struct power_supply *battery, u32 *index) { - const char *uid_str; + u32 serial_dec, serial_hex, serial; + union power_supply_propval val; + int ret; - uid_str = acpi_device_uid(acpi_dev); - if (!uid_str) - return -ENODEV; + guard(mutex)(&data->translation_cache_lock); - return kstrtou32(uid_str, 10, index); + for (int i = 0; i < ARRAY_SIZE(data->translation_cache); i++) { + if (data->translation_cache[i] == battery) { + dev_dbg(&data->wdev->dev, "Translation cache hit for battery index %u\n", + i + 1); + *index = i + 1; + return 0; + } + } + + dev_dbg(&data->wdev->dev, "Translation cache miss\n"); + + /* Perform a translation between a ACPI battery and a battery index */ + + ret = power_supply_get_property(battery, POWER_SUPPLY_PROP_SERIAL_NUMBER, &val); + if (ret < 0) + return ret; + + /* + * Some devices display the serial number of the ACPI battery (string!) as a decimal + * number while other devices display it as a hexadecimal number. Because of this we + * have to check both cases. + */ + ret = kstrtou32(val.strval, 16, &serial_hex); + if (ret < 0) + return ret; /* Should never fail */ + + ret = kstrtou32(val.strval, 10, &serial_dec); + if (ret < 0) + serial_dec = 0; /* Can fail, thus we only mark serial_dec as invalid */ + + for (int i = 0; i < ARRAY_SIZE(data->translation_cache); i++) { + ret = dell_wmi_ddv_query_integer(data->wdev, DELL_DDV_BATTERY_SERIAL_NUMBER, i + 1, + &serial); + if (ret < 0) + return ret; + + /* A serial number of 0 signals that this index is not associated with a battery */ + if (!serial) + continue; + + if (serial == serial_dec || serial == serial_hex) { + dev_dbg(&data->wdev->dev, "Translation cache update for battery index %u\n", + i + 1); + data->translation_cache[i] = battery; + *index = i + 1; + return 0; + } + } + + return -ENODEV; +} + +static void dell_wmi_battery_invalidate(struct dell_wmi_ddv_data *data, + struct power_supply *battery) +{ + guard(mutex)(&data->translation_cache_lock); + + for (int i = 0; i < ARRAY_SIZE(data->translation_cache); i++) { + if (data->translation_cache[i] == battery) { + data->translation_cache[i] = NULL; + return; + } + } } static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -657,7 +725,7 @@ static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, cha u32 index; int ret; - ret = dell_wmi_ddv_battery_index(to_acpi_device(dev->parent), &index); + ret = dell_wmi_ddv_battery_translate(data, to_power_supply(dev), &index); if (ret < 0) return ret; @@ -684,7 +752,7 @@ static int dell_wmi_ddv_get_property(struct power_supply *psy, const struct powe u32 index, value; int ret; - ret = dell_wmi_ddv_battery_index(to_acpi_device(psy->dev.parent), &index); + ret = dell_wmi_ddv_battery_translate(data, psy, &index); if (ret < 0) return ret; @@ -719,13 +787,12 @@ static const struct power_supply_ext dell_wmi_ddv_extension = { static int dell_wmi_ddv_add_battery(struct power_supply *battery, struct acpi_battery_hook *hook) { struct dell_wmi_ddv_data *data = container_of(hook, struct dell_wmi_ddv_data, hook); - u32 index; int ret; - /* Return 0 instead of error to avoid being unloaded */ - ret = dell_wmi_ddv_battery_index(to_acpi_device(battery->dev.parent), &index); - if (ret < 0) - return 0; + /* + * We cannot do the battery matching here since the battery might be absent, preventing + * us from reading the serial number. + */ ret = device_create_file(&battery->dev, &data->eppid_attr); if (ret < 0) @@ -749,11 +816,19 @@ static int dell_wmi_ddv_remove_battery(struct power_supply *battery, struct acpi device_remove_file(&battery->dev, &data->eppid_attr); power_supply_unregister_extension(battery, &dell_wmi_ddv_extension); + dell_wmi_battery_invalidate(data, battery); + return 0; } static int dell_wmi_ddv_battery_add(struct dell_wmi_ddv_data *data) { + int ret; + + ret = devm_mutex_init(&data->wdev->dev, &data->translation_cache_lock); + if (ret < 0) + return ret; + data->hook.name = "Dell DDV Battery Extension"; data->hook.add_battery = dell_wmi_ddv_add_battery; data->hook.remove_battery = dell_wmi_ddv_remove_battery;