[Intel-gfx] [PATCH v3 2/5] drm/i915: Force recalculate min_cdclk if planes config changed

[Stanislav Lisovskiy]

In Gen11+ whenever we might exceed DBuf bandwidth we might need to
recalculate CDCLK which DBuf bandwidth is scaled with.
Total Dbuf bw used might change based on particular plane needs.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 17d83f37f49f..9fd32d61ebfe 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14623,7 +14623,7 @@ static bool active_planes_affects_min_cdclk(struct drm_i915_private *dev_priv)
 	/* See {hsw,vlv,ivb}_plane_ratio() */
 	return IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv) ||
 		IS_CHERRYVIEW(dev_priv) || IS_VALLEYVIEW(dev_priv) ||
-		IS_IVYBRIDGE(dev_priv);
+		IS_IVYBRIDGE(dev_priv) || (INTEL_GEN(dev_priv) >= 11);
 }
 
 static int intel_atomic_check_planes(struct intel_atomic_state *state,
@@ -14669,7 +14669,13 @@ static int intel_atomic_check_planes(struct intel_atomic_state *state,
 		old_active_planes = old_crtc_state->active_planes & ~BIT(PLANE_CURSOR);
 		new_active_planes = new_crtc_state->active_planes & ~BIT(PLANE_CURSOR);
 
-		if (hweight8(old_active_planes) == hweight8(new_active_planes))
+		/*
+		 * Not only the number of planes, but if the plane configuration had
+		 * changed might already mean we need to recompute min CDCLK,
+		 * because different planes might consume different amount of Dbuf bandwidth
+		 * according to formula: Bw per plane = Pixel rate * bpp * pipe/plane scale factor
+		 */
+		if (old_active_planes == new_active_planes)
 			continue;
 
 		ret = intel_crtc_add_planes_to_state(state, crtc, new_active_planes);
-- 
2.24.1.485.gad05a3d8e5