diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 77b153093cf14541d47a5eda240d9f433bf8bca0..3297cf1a14ed3b4f0fa75e0ef8c09f2c49701314 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3245,6 +3245,7 @@
 #define  TRANS_DP_PORT_SEL_B	(0<<29)
 #define  TRANS_DP_PORT_SEL_C	(1<<29)
 #define  TRANS_DP_PORT_SEL_D	(2<<29)
+#define  TRANS_DP_PORT_SEL_NONE	(3<<29)
 #define  TRANS_DP_PORT_SEL_MASK	(3<<29)
 #define  TRANS_DP_AUDIO_ONLY	(1<<26)
 #define  TRANS_DP_ENH_FRAMING	(1<<18)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a4acef6c14743658b0c012889ee4427f6f0b5264..b5f7acf5a9dbccf862bfa953827193e58c0e24fb 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2818,6 +2818,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 		reg = TRANS_DP_CTL(pipe);
 		temp = I915_READ(reg);
 		temp &= ~(TRANS_DP_OUTPUT_ENABLE | TRANS_DP_PORT_SEL_MASK);
+		temp |= TRANS_DP_PORT_SEL_NONE;
 		I915_WRITE(reg, temp);
 
 		/* disable DPLL_SEL */