diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index cb50c527401f..c8103f8d4dfa 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -888,10 +888,14 @@ static void pch_enable_backlight(struct intel_connector *connector)
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	struct intel_panel *panel = &connector->panel;
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
-	enum transcoder cpu_transcoder =
-		intel_pipe_to_cpu_transcoder(dev_priv, pipe);
+	enum transcoder cpu_transcoder;
 	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
 
+	if (!WARN_ON_ONCE(pipe == INVALID_PIPE))
+		cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv, pipe);
+	else
+		cpu_transcoder = TRANSCODER_EDP;
+
 	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
 	if (cpu_ctl2 & BLM_PWM_ENABLE) {
 		DRM_DEBUG_KMS("cpu backlight already enabled\n");
@@ -973,6 +977,9 @@ static void i965_enable_backlight(struct intel_connector *connector)
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
 	u32 ctl, ctl2, freq;
 
+	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
+		pipe = PIPE_A;
+
 	ctl2 = I915_READ(BLC_PWM_CTL2);
 	if (ctl2 & BLM_PWM_ENABLE) {
 		DRM_DEBUG_KMS("backlight already enabled\n");
@@ -1037,6 +1044,9 @@ static void bxt_enable_backlight(struct intel_connector *connector)
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
 	u32 pwm_ctl, val;
 
+	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
+		pipe = PIPE_A;
+
 	/* Controller 1 uses the utility pin. */
 	if (panel->backlight.controller == 1) {
 		val = I915_READ(UTIL_PIN_CTL);
@@ -1093,7 +1103,8 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 	if (!panel->backlight.present)
 		return;
 
-	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
+	if (!WARN_ON_ONCE(pipe == INVALID_PIPE))
+		DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
 
 	mutex_lock(&dev_priv->backlight_lock);