3 files changed, 38 insertions, 19 deletions

diff --git a/drivers/gpu/drm/nouveau/dispnv50/Kbuild b/drivers/gpu/drm/nouveau/dispnv50/Kbuild
index 475c630308d1..e0c435eae664 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/Kbuild
+++ b/drivers/gpu/drm/nouveau/dispnv50/Kbuild
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: GPL-2.0
+# SPDX-License-Identifier: MIT
 nouveau-y += dispnv50/disp.o
 nouveau-y += dispnv50/lut.o
 
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 4b1650f51955..8497768f1b41 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -322,8 +322,13 @@ nv50_outp_atomic_check_view(struct drm_encoder *encoder,
 		switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_LVDS:
 		case DRM_MODE_CONNECTOR_eDP:
-			/* Force use of scaler for non-EDID modes. */
-			if (adjusted_mode->type & DRM_MODE_TYPE_DRIVER)
+			/* Don't force scaler for EDID modes with
+			 * same size as the native one (e.g. different
+			 * refresh rate)
+			 */
+			if (adjusted_mode->hdisplay == native_mode->hdisplay &&
+			    adjusted_mode->vdisplay == native_mode->vdisplay &&
+			    adjusted_mode->type & DRM_MODE_TYPE_DRIVER)
 				break;
 			mode = native_mode;
 			asyc->scaler.full = true;
@@ -948,11 +953,12 @@ nv50_mstc_get_modes(struct drm_connector *connector)
 
 static int
 nv50_mstc_atomic_check(struct drm_connector *connector,
-		       struct drm_connector_state *new_conn_state)
+		       struct drm_atomic_state *state)
 {
-	struct drm_atomic_state *state = new_conn_state->state;
 	struct nv50_mstc *mstc = nv50_mstc(connector);
 	struct drm_dp_mst_topology_mgr *mgr = &mstc->mstm->mgr;
+	struct drm_connector_state *new_conn_state =
+		drm_atomic_get_new_connector_state(state, connector);
 	struct drm_connector_state *old_conn_state =
 		drm_atomic_get_old_connector_state(state, connector);
 	struct drm_crtc_state *crtc_state;
diff --git a/drivers/gpu/drm/nouveau/dispnv50/head.c b/drivers/gpu/drm/nouveau/dispnv50/head.c
index 06ee23823a68..929d93b1677e 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/head.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/head.c
@@ -169,14 +169,34 @@ nv50_head_atomic_check_view(struct nv50_head_atom *armh,
 	 */
 	switch (mode) {
 	case DRM_MODE_SCALE_CENTER:
-		asyh->view.oW = min((u16)umode->hdisplay, asyh->view.oW);
-		asyh->view.oH = min((u16)umode_vdisplay, asyh->view.oH);
-		/* fall-through */
+		/* NOTE: This will cause scaling when the input is
+		 * larger than the output.
+		 */
+		asyh->view.oW = min(asyh->view.iW, asyh->view.oW);
+		asyh->view.oH = min(asyh->view.iH, asyh->view.oH);
+		break;
 	case DRM_MODE_SCALE_ASPECT:
-		if (asyh->view.oH < asyh->view.oW) {
+		/* Determine whether the scaling should be on width or on
+		 * height. This is done by comparing the aspect ratios of the
+		 * sizes. If the output AR is larger than input AR, that means
+		 * we want to change the width (letterboxed on the
+		 * left/right), otherwise on the height (letterboxed on the
+		 * top/bottom).
+		 *
+		 * E.g. 4:3 (1.333) AR image displayed on a 16:10 (1.6) AR
+		 * screen will have letterboxes on the left/right. However a
+		 * 16:9 (1.777) AR image on that same screen will have
+		 * letterboxes on the top/bottom.
+		 *
+		 * inputAR = iW / iH; outputAR = oW / oH
+		 * outputAR > inputAR is equivalent to oW * iH > iW * oH
+		 */
+		if (asyh->view.oW * asyh->view.iH > asyh->view.iW * asyh->view.oH) {
+			/* Recompute output width, i.e. left/right letterbox */
 			u32 r = (asyh->view.iW << 19) / asyh->view.iH;
 			asyh->view.oW = ((asyh->view.oH * r) + (r / 2)) >> 19;
 		} else {
+			/* Recompute output height, i.e. top/bottom letterbox */
 			u32 r = (asyh->view.iH << 19) / asyh->view.iW;
 			asyh->view.oH = ((asyh->view.oW * r) + (r / 2)) >> 19;
 		}
@@ -421,16 +441,6 @@ nv50_head_atomic_duplicate_state(struct drm_crtc *crtc)
 }
 
 static void
-__drm_atomic_helper_crtc_reset(struct drm_crtc *crtc,
-			       struct drm_crtc_state *state)
-{
-	if (crtc->state)
-		crtc->funcs->atomic_destroy_state(crtc, crtc->state);
-	crtc->state = state;
-	crtc->state->crtc = crtc;
-}
-
-static void
 nv50_head_reset(struct drm_crtc *crtc)
 {
 	struct nv50_head_atom *asyh;
@@ -438,6 +448,9 @@ nv50_head_reset(struct drm_crtc *crtc)
 	if (WARN_ON(!(asyh = kzalloc(sizeof(*asyh), GFP_KERNEL))))
 		return;
 
+	if (crtc->state)
+		nv50_head_atomic_destroy_state(crtc, crtc->state);
+
 	__drm_atomic_helper_crtc_reset(crtc, &asyh->state);
 }