drm/i915: Convert cdclk to global state

Let's convert cdclk_state to be a proper global state. That allows
us to use the regular atomic old vs. new state accessor, hopefully
making the code less confusing.

We do have to deal with a few more error cases in case the cdclk
state duplication fails. But so be it.

v2: Fix new plane min_cdclk vs. old crtc min_cdclk check

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200121140353.25997-1-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>

1 files changed, 44 insertions, 25 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
index 7367ad0bf27c..91ab6e2ab1fd 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
@@ -37,6 +37,7 @@
 
 #include "i915_trace.h"
 #include "intel_atomic_plane.h"
+#include "intel_cdclk.h"
 #include "intel_display_types.h"
 #include "intel_pm.h"
 #include "intel_sprite.h"
@@ -155,45 +156,63 @@ unsigned int intel_plane_data_rate(const struct intel_crtc_state *crtc_state,
 	return cpp * crtc_state->pixel_rate;
 }
 
-bool intel_plane_calc_min_cdclk(struct intel_atomic_state *state,
-				struct intel_plane *plane)
+int intel_plane_calc_min_cdclk(struct intel_atomic_state *state,
+			       struct intel_plane *plane,
+			       bool *need_cdclk_calc)
 {
 	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
-	const struct intel_cdclk_state *cdclk_state =
-		&dev_priv->cdclk_state;
 	const struct intel_plane_state *plane_state =
 		intel_atomic_get_new_plane_state(state, plane);
 	struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc);
-	struct intel_crtc_state *crtc_state;
+	const struct intel_cdclk_state *cdclk_state;
+	struct intel_crtc_state *new_crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+	const struct intel_crtc_state *old_crtc_state =
+		intel_atomic_get_old_crtc_state(state, crtc);
 
 	if (!plane_state->uapi.visible || !plane->min_cdclk)
-		return false;
+		return 0;
+
+	new_crtc_state->min_cdclk[plane->id] =
+		plane->min_cdclk(new_crtc_state, plane_state);
 
-	crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
+	/*
+	 * No need to check against the cdclk state if
+	 * the min cdclk for the plane doesn't increase.
+	 *
+	 * Ie. we only ever increase the cdclk due to plane
+	 * requirements. This can reduce back and forth
+	 * display blinking due to constant cdclk changes.
+	 */
+	if (new_crtc_state->min_cdclk[plane->id] <=
+	    old_crtc_state->min_cdclk[plane->id])
+		return 0;
 
-	crtc_state->min_cdclk[plane->id] =
-		plane->min_cdclk(crtc_state, plane_state);
+	cdclk_state = intel_atomic_get_cdclk_state(state);
+	if (IS_ERR(cdclk_state))
+		return PTR_ERR(cdclk_state);
 
 	/*
-	 * Does the cdclk need to be bumbed up?
+	 * No need to recalculate the cdclk state if
+	 * the min cdclk for the pipe doesn't increase.
 	 *
-	 * Note: we obviously need to be called before the new
-	 * cdclk frequency is calculated so state->cdclk.logical
-	 * hasn't been populated yet. Hence we look at the old
-	 * cdclk state under dev_priv->cdclk.logical. This is
-	 * safe as long we hold at least one crtc mutex (which
-	 * must be true since we have crtc_state).
+	 * Ie. we only ever increase the cdclk due to plane
+	 * requirements. This can reduce back and forth
+	 * display blinking due to constant cdclk changes.
 	 */
-	if (crtc_state->min_cdclk[plane->id] > cdclk_state->logical.cdclk) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "[PLANE:%d:%s] min_cdclk (%d kHz) > logical cdclk (%d kHz)\n",
-			    plane->base.base.id, plane->base.name,
-			    crtc_state->min_cdclk[plane->id],
-			    cdclk_state->logical.cdclk);
-		return true;
-	}
+	if (new_crtc_state->min_cdclk[plane->id] <=
+	    cdclk_state->min_cdclk[crtc->pipe])
+		return 0;
+
+	drm_dbg_kms(&dev_priv->drm,
+		    "[PLANE:%d:%s] min cdclk (%d kHz) > [CRTC:%d:%s] min cdclk (%d kHz)\n",
+		    plane->base.base.id, plane->base.name,
+		    new_crtc_state->min_cdclk[plane->id],
+		    crtc->base.base.id, crtc->base.name,
+		    cdclk_state->min_cdclk[crtc->pipe]);
+	*need_cdclk_calc = true;
 
-	return false;
+	return 0;
 }
 
 static void intel_plane_clear_hw_state(struct intel_plane_state *plane_state)