diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
index a90f2545baee0c7e6b541cc1d957c7dad6c286a4..db63f4e11b171e3cfd20e987251d50c0791f786b 100644
--- a/drivers/gpu/drm/vc4/vc4_dpi.c
+++ b/drivers/gpu/drm/vc4/vc4_dpi.c
@@ -178,8 +178,8 @@ static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
 			break;
 		}
 	} else {
-		/* Default to 24bit if no connector found. */
-		dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
+		/* Default to 18bit if no connector found. */
+		dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1, DPI_FORMAT);
 	}
 
 	if (mode->flags & DRM_MODE_FLAG_NHSYNC)