diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 24ecb486465b..f98a403c6625 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1567,7 +1567,7 @@ static void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
 
 		I915_WRITE(DPLL_CTRL2, val);
 
-	} else {
+	} else if (INTEL_INFO(dev)->gen < 9) {
 		WARN_ON(crtc->config->ddi_pll_sel == PORT_CLK_SEL_NONE);
 		I915_WRITE(PORT_CLK_SEL(port), crtc->config->ddi_pll_sel);
 	}
@@ -1626,7 +1626,7 @@ static void intel_ddi_post_disable(struct intel_encoder *intel_encoder)
 	if (IS_SKYLAKE(dev))
 		I915_WRITE(DPLL_CTRL2, (I915_READ(DPLL_CTRL2) |
 					DPLL_CTRL2_DDI_CLK_OFF(port)));
-	else
+	else if (INTEL_INFO(dev)->gen < 9)
 		I915_WRITE(PORT_CLK_SEL(port), PORT_CLK_SEL_NONE);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 73350894e2c9..3945057c5bbe 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -173,8 +173,10 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder)
 	if (intel_dp->active_mst_links == 0) {
 		enum port port = intel_ddi_get_encoder_port(encoder);
 
-		I915_WRITE(PORT_CLK_SEL(port),
-			   intel_crtc->config->ddi_pll_sel);
+		/* FIXME: add support for SKL */
+		if (INTEL_INFO(dev)->gen < 9)
+			I915_WRITE(PORT_CLK_SEL(port),
+				   intel_crtc->config->ddi_pll_sel);
 
 		intel_ddi_init_dp_buf_reg(&intel_dig_port->base);