drm/i915: use sw tracked state to select shared dplls

Just yet another prep step to be able to do all this up-front, before
we've set up any of the shared dplls in the new state. This will
eventually be useful for atomic modesetting.
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -3031,7 +3031,7 @@ static void intel_put_shared_dpll(struct intel_crtc *crtc)
 	crtc->config.shared_dpll = DPLL_ID_PRIVATE;
 }
 
-static struct intel_shared_dpll *intel_get_shared_dpll(struct intel_crtc *crtc, u32 dpll, u32 fp)
+static struct intel_shared_dpll *intel_get_shared_dpll(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
 	struct intel_shared_dpll *pll = intel_crtc_to_shared_dpll(crtc);
@@ -3061,8 +3061,8 @@ static struct intel_shared_dpll *intel_get_shared_dpll(struct intel_crtc *crtc,
 		if (pll->refcount == 0)
 			continue;
 
-		if (dpll == (I915_READ(PCH_DPLL(pll->id)) & 0x7fffffff) &&
-		    fp == I915_READ(PCH_FP0(pll->id))) {
+		if (memcmp(&crtc->config.dpll_hw_state, &pll->hw_state,
+			   sizeof(pll->hw_state)) == 0) {
 			DRM_DEBUG_KMS("CRTC:%d sharing existing %s (refcount %d, ative %d)\n",
 				      crtc->base.base.id,
 				      pll->name, pll->refcount, pll->active);
@@ -5701,7 +5701,7 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 		else
 			intel_crtc->config.dpll_hw_state.fp1 = fp;
 
-		pll = intel_get_shared_dpll(intel_crtc, dpll, fp);
+		pll = intel_get_shared_dpll(intel_crtc);
 		if (pll == NULL) {
 			DRM_DEBUG_DRIVER("failed to find PLL for pipe %c\n",
 					 pipe_name(pipe));