drm/i915: Move stuff into intel_dpll_crtc_compute_clock()

Move some checks into intel_dpll_crtc_compute_clock() from the
caller. Avoids the caller from having to worry about all this
crap.

We'll also reorder the hw.enable vs. shared_dpll checks since
it makes sense to sanity check that we've cleared out the
old shared_dpll even if the pipe is getting disabled.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220325123205.22140-6-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -4904,8 +4904,7 @@ static int intel_crtc_atomic_check(struct intel_atomic_state *state,
 	    mode_changed && !crtc_state->hw.active)
 		crtc_state->update_wm_post = true;
 
-	if (mode_changed && crtc_state->hw.enable &&
-	    !drm_WARN_ON(&dev_priv->drm, crtc_state->shared_dpll)) {
+	if (mode_changed) {
 		ret = intel_dpll_crtc_compute_clock(state, crtc);
 		if (ret)
 			return ret;

drivers/gpu/drm/i915/display/intel_dpll.c

@@ -1419,6 +1419,16 @@ int intel_dpll_crtc_compute_clock(struct intel_atomic_state *state,
 				  struct intel_crtc *crtc)
 {
 	struct drm_i915_private *i915 = to_i915(state->base.dev);
+	struct intel_crtc_state *crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+
+	drm_WARN_ON(&i915->drm, !intel_crtc_needs_modeset(crtc_state));
+
+	if (drm_WARN_ON(&i915->drm, crtc_state->shared_dpll))
+		return 0;
+
+	if (!crtc_state->hw.enable)
+		return 0;
 
 	return i915->dpll_funcs->crtc_compute_clock(state, crtc);
 }