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>
---
 drivers/hwmon/acpi_power_meter.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
index 2f1c9d97ad21..dcf86794485f 100644
--- 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;
-- 
2.22.0

On Thu, Jan 09, 2025 at 04:17:07PM +0800, Huisong Li wrote:
> 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>

Applied.

Thanks,
Guenter