hwmon: (acpi_power_meter) Fix uninitialized variables

The 'power1_alarm' attribute uses the 'power' and 'cap' in the
acpi_power_meter_resource structure. Currently, these two fields are just
updated when user query 'power' and 'cap' attribute. If user directly query
the 'power1_alarm' attribute without queryng above two attributes, driver
will use uninitialized variables to judge.

So this patch adds the setting of alarm state and update 'cap' in the
notification callback and update 'power' and 'cap' if needed to show the
real alarm state.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Link: https://lore.kernel.org/r/20250109081708.27366-2-lihuisong@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
index 2f1c9d97ad2118537355638b13fae948e8a82110..dcf86794485fe0b73d1a572cb866a28021f91d41 100644 (file)
--- a/drivers/hwmon/acpi_power_meter.c
+++ b/drivers/hwmon/acpi_power_meter.c
@@ -84,6 +84,7 @@ struct acpi_power_meter_resource {
        u64             power;
        u64             cap;
        u64             avg_interval;
+       bool            power_alarm;
        int                     sensors_valid;
        unsigned long           sensors_last_updated;
        struct sensor_device_attribute  sensors[NUM_SENSORS];
@@ -396,6 +397,9 @@ static ssize_t show_val(struct device *dev,
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
        u64 val = 0;
+       int ret;
+
+       guard(mutex)(&resource->lock);
 
        switch (attr->index) {
        case 0:
@@ -423,10 +427,17 @@ static ssize_t show_val(struct device *dev,
                        val = 0;
                break;
        case 6:
-               if (resource->power > resource->cap)
-                       val = 1;
-               else
-                       val = 0;
+               ret = update_meter(resource);
+               if (ret)
+                       return ret;
+               /* need to update cap if not to support the notification. */
+               if (!(resource->caps.flags & POWER_METER_CAN_NOTIFY)) {
+                       ret = update_cap(resource);
+                       if (ret)
+                               return ret;
+               }
+               val = resource->power_alarm || resource->power > resource->cap;
+               resource->power_alarm = resource->power > resource->cap;
                break;
        case 7:
        case 8:
@@ -847,12 +858,20 @@ static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
                sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
                break;
        case METER_NOTIFY_CAP:
+               mutex_lock(&resource->lock);
+               res = update_cap(resource);
+               if (res)
+                       dev_err_once(&device->dev, "update cap failed when capping value is changed.\n");
+               mutex_unlock(&resource->lock);
                sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
                break;
        case METER_NOTIFY_INTERVAL:
                sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
                break;
        case METER_NOTIFY_CAPPING:
+               mutex_lock(&resource->lock);
+               resource->power_alarm = true;
+               mutex_unlock(&resource->lock);
                sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
                dev_info(&device->dev, "Capping in progress.\n");
                break;