diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 65adb9c..31be81e 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -77,9 +77,12 @@ atombios_get_backlight_level(struct radeon_encoder *radeon_encoder)
 	struct drm_device *dev = radeon_encoder->base.dev;
 	struct radeon_device *rdev = dev->dev_private;
 
-	if (!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU))
+	if (WARN_ON(!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU)))
 		return 0;
 
+	DRM_INFO("Backlight controlled by GPU, current level %u\n",
+		 radeon_atom_get_backlight_level_from_reg(rdev));
+
 	return radeon_atom_get_backlight_level_from_reg(rdev);
 }
 
@@ -93,7 +96,7 @@ atombios_set_backlight_level(struct radeon_encoder *radeon_encoder, u8 level)
 	DISPLAY_DEVICE_OUTPUT_CONTROL_PS_ALLOCATION args;
 	int index;
 
-	if (!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU))
+	if (WARN_ON(!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU)))
 		return;
 
 	if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
@@ -105,6 +108,7 @@ atombios_set_backlight_level(struct radeon_encoder *radeon_encoder, u8 level)
 		switch (radeon_encoder->encoder_id) {
 		case ENCODER_OBJECT_ID_INTERNAL_LVDS:
 		case ENCODER_OBJECT_ID_INTERNAL_LVTM1:
+			DRM_INFO("Setting LVDS backlight level to %u\n", level);
 			index = GetIndexIntoMasterTable(COMMAND, LCD1OutputControl);
 			if (dig->backlight_level == 0) {
 				args.ucAction = ATOM_LCD_BLOFF;
@@ -120,6 +124,7 @@ atombios_set_backlight_level(struct radeon_encoder *radeon_encoder, u8 level)
 		case ENCODER_OBJECT_ID_INTERNAL_KLDSCP_LVTMA:
 		case ENCODER_OBJECT_ID_INTERNAL_UNIPHY1:
 		case ENCODER_OBJECT_ID_INTERNAL_UNIPHY2:
+			DRM_INFO("Setting UNIPHY backlight level to %u\n", level);
 			if (dig->backlight_level == 0)
 				atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_LCD_BLOFF, 0, 0);
 			else {
@@ -199,7 +204,7 @@ void radeon_atom_backlight_init(struct radeon_encoder *radeon_encoder,
 	if (!rdev->is_atom_bios)
 		return;
 
-	if (!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU))
+	if (WARN_ON(!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU)))
 		return;
 
 	pdata = kmalloc(sizeof(struct radeon_backlight_privdata), GFP_KERNEL);