drm/i915: Skip DDI PLL selection for DSI

Skip DDI PLL selection if display type is DSI/MIPI.
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1454671768-27062-1-git-send-email-mika.kahola@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -9848,8 +9848,13 @@ static void broadwell_modeset_commit_cdclk(struct drm_atomic_state *old_state)
 static int haswell_crtc_compute_clock(struct intel_crtc *crtc,
 				      struct intel_crtc_state *crtc_state)
 {
-	if (!intel_ddi_pll_select(crtc, crtc_state))
-		return -EINVAL;
+	struct intel_encoder *intel_encoder =
+		intel_ddi_get_crtc_new_encoder(crtc_state);
+
+	if (intel_encoder->type != INTEL_OUTPUT_DSI) {
+		if (!intel_ddi_pll_select(crtc, crtc_state))
+			return -EINVAL;
+	}
 
 	crtc->lowfreq_avail = false;