fix: Don't wake up the display if it's turned off

The tickers only need to be reset, if they're disabled, they won't have
been started.

display.go

@@ -157,20 +157,21 @@ func wakeDisplay(force bool) {
 		return
 	}
 
+	// Don't try to wake up if the display is turned off.
+	if config.DisplayMaxBrightness == 0 {
+		return
+	}
+
 	err := setDisplayBrightness(config.DisplayMaxBrightness)
 	if err != nil {
 		fmt.Printf("display wake failed, %s\n", err)
 	}
 
-	if config.DisplayDimAfterSec == 0 {
+	if config.DisplayDimAfterSec != 0 {
-		dimTicker.Stop()
-	} else {
 		dimTicker.Reset(time.Duration(config.DisplayDimAfterSec) * time.Second)
 	}
 
-	if config.DisplayOffAfterSec == 0 {
+	if config.DisplayOffAfterSec != 0 {
-		offTicker.Stop()
-	} else {
 		offTicker.Reset(time.Duration(config.DisplayOffAfterSec) * time.Second)
 	}
 	backlightState = 0
@@ -209,8 +210,15 @@ func watchTsEvents() {
 // option has the value set to zero, but time.NewTicker only accept positive values.
 func startBacklightTickers() {
 	LoadConfig()
+	// Don't start the tickers if the display is switched off.
+	// Set the display to off if that's the case.
+	if config.DisplayMaxBrightness == 0 {
+		setDisplayBrightness(0)
+		return
+	}
+
 	if dimTicker == nil && config.DisplayDimAfterSec != 0 {
-		fmt.Printf("display: dim_ticker has started.")
+		fmt.Printf("display: dim_ticker has started\n")
 		dimTicker = time.NewTicker(time.Duration(config.DisplayDimAfterSec) * time.Second)
 		defer dimTicker.Stop()
 
@@ -225,7 +233,7 @@ func startBacklightTickers() {
 	}
 
 	if offTicker == nil && config.DisplayOffAfterSec != 0 {
-		fmt.Printf("display: off_ticker has started.")
+		fmt.Printf("display: off_ticker has started\n")
 		offTicker = time.NewTicker(time.Duration(config.DisplayOffAfterSec) * time.Second)
 		defer offTicker.Stop()
 
@@ -248,9 +256,9 @@ func init() {
 		updateStaticContents()
 		displayInited = true
 		fmt.Println("display inited")
-		wakeDisplay(false)
-		requestDisplayUpdate()
 		startBacklightTickers()
+		wakeDisplay(true)
+		requestDisplayUpdate()
 	}()
 
 	go watchTsEvents()