fix(agent): SKIP_GPU excludes GPU hwmon from temperatures and fans (#2313)

agent/fans.go

@@ -12,7 +12,7 @@ import (
 )
 
 type fanSensor struct {
-	key, path string
+	key, path, chip string
 }
 
 var getFanSensors = newFanSensorCache(hwmonRoot)
@@ -34,6 +34,10 @@ func (a *Agent) updateFans(systemStats *system.Stats) {
 		slog.Debug("Error reading fans", "err", err)
 		return
 	}
+	// Filter before reading fan*_input: each read can wake an idle GPU.
+	if a.sensorConfig != nil && a.sensorConfig.skipGPU {
+		sensors = filterGpuFans(sensors)
+	}
 	fans := readFanSensors(sensors)
 	if len(fans) == 0 {
 		return
@@ -100,7 +104,7 @@ func discoverHwmonFans(root string) ([]fanSensor, error) {
 			if label != "" {
 				key = chipName + "_" + label
 			}
-			sensors = append(sensors, fanSensor{key, inputPath})
+			sensors = append(sensors, fanSensor{key, inputPath, chipName})
 		}
 	}
 	return sensors, nil
@@ -115,3 +119,15 @@ func readFanSensors(sensors []fanSensor) map[string]uint16 {
 	}
 	return fans
 }
+
+// filterGpuFans drops GPU chips without touching the shared cache backing array.
+func filterGpuFans(sensors []fanSensor) []fanSensor {
+	kept := make([]fanSensor, 0, len(sensors))
+	for _, sensor := range sensors {
+		if isGpuChipName(sensor.chip) {
+			continue
+		}
+		kept = append(kept, sensor)
+	}
+	return kept
+}