add warn log if predicted brightness is outside of min:max range

Author: max-baz

src/brightness/backlight.rs

@@ -130,8 +130,11 @@ impl Backlight {
         }
     }
 
-    pub async fn set(&mut self, value: u64) -> Result<u64> {
-        let value = value.clamp(self.min_brightness, self.max_brightness);
+    pub async fn set(&mut self, desired_value: u64) -> Result<u64> {
+        let value = desired_value.clamp(self.min_brightness, self.max_brightness);
+        if value != desired_value {
+            log::warn!("Attempted to set brightness to {desired_value}, clamping it to {value} (min: {}, max: {}), please report if you see this often", self.min_brightness, self.max_brightness);
+        }
 
         if self.has_write_permission {
             write(&mut self.file, value as f64).await?;