diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
index 19efdd3318b6..0bde6a4259fd 100644
--- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
@@ -1296,7 +1296,15 @@ static void bxt_ddi_pll_enable(struct drm_i915_private *dev_priv,
 	enum port port = (enum port)pll->id;	/* 1:1 port->PLL mapping */
 
 	temp = I915_READ(BXT_PORT_PLL_ENABLE(port));
-	temp &= ~PORT_PLL_REF_SEL;
+	/*
+	 * Definition of each bit polarity has been changed
+	 * after A1 stepping
+	 */
+	if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1))
+		temp &= ~PORT_PLL_REF_SEL;
+	else
+		temp |= PORT_PLL_REF_SEL;
+
 	/* Non-SSC reference */
 	I915_WRITE(BXT_PORT_PLL_ENABLE(port), temp);