From 5724c842dafe7ca2f2203e7b2dbaf704aa18b49c Mon Sep 17 00:00:00 2001
From: Jonathan Gray <jsg@cvs.openbsd.org>
Date: Mon, 1 Jan 2024 23:47:02 +0000
Subject: drm/i915/mtl: limit second scaler vertical scaling in ver >= 14

From Luca Coelho
99767368b7fad6bee30ca89ef96877d86e3181a1 in linux-6.1.y/6.1.70
8d4312e2b228ba7a5ac79154458098274ec61e9b in mainline linux
---
 sys/dev/pci/drm/i915/display/intel_atomic.c | 85 +++++++++++++++++++++++++----
 1 file changed, 75 insertions(+), 10 deletions(-)

(limited to 'sys/dev/pci')

diff --git a/sys/dev/pci/drm/i915/display/intel_atomic.c b/sys/dev/pci/drm/i915/display/intel_atomic.c
index 18f0a5ae3ba..61dda54d68e 100644
--- a/sys/dev/pci/drm/i915/display/intel_atomic.c
+++ b/sys/dev/pci/drm/i915/display/intel_atomic.c
@@ -41,6 +41,7 @@
 #include "intel_global_state.h"
 #include "intel_hdcp.h"
 #include "intel_psr.h"
+#include "intel_fb.h"
 #include "skl_universal_plane.h"
 
 /**
@@ -302,11 +303,11 @@ intel_crtc_destroy_state(struct drm_crtc *crtc,
 	kfree(crtc_state);
 }
 
-static void intel_atomic_setup_scaler(struct intel_crtc_scaler_state *scaler_state,
-				      int num_scalers_need, struct intel_crtc *intel_crtc,
-				      const char *name, int idx,
-				      struct intel_plane_state *plane_state,
-				      int *scaler_id)
+static int intel_atomic_setup_scaler(struct intel_crtc_scaler_state *scaler_state,
+				     int num_scalers_need, struct intel_crtc *intel_crtc,
+				     const char *name, int idx,
+				     struct intel_plane_state *plane_state,
+				     int *scaler_id)
 {
 	struct drm_i915_private *dev_priv = to_i915(intel_crtc->base.dev);
 	int j;
@@ -326,7 +327,7 @@ static void intel_atomic_setup_scaler(struct intel_crtc_scaler_state *scaler_sta
 
 	if (drm_WARN(&dev_priv->drm, *scaler_id < 0,
 		     "Cannot find scaler for %s:%d\n", name, idx))
-		return;
+		return -EINVAL;
 
 	/* set scaler mode */
 	if (plane_state && plane_state->hw.fb &&
@@ -367,9 +368,71 @@ static void intel_atomic_setup_scaler(struct intel_crtc_scaler_state *scaler_sta
 		mode = SKL_PS_SCALER_MODE_DYN;
 	}
 
+	/*
+	 * FIXME: we should also check the scaler factors for pfit, so
+	 * this shouldn't be tied directly to planes.
+	 */
+	if (plane_state && plane_state->hw.fb) {
+		const struct drm_framebuffer *fb = plane_state->hw.fb;
+		const struct drm_rect *src = &plane_state->uapi.src;
+		const struct drm_rect *dst = &plane_state->uapi.dst;
+		int hscale, vscale, max_vscale, max_hscale;
+
+		/*
+		 * FIXME: When two scalers are needed, but only one of
+		 * them needs to downscale, we should make sure that
+		 * the one that needs downscaling support is assigned
+		 * as the first scaler, so we don't reject downscaling
+		 * unnecessarily.
+		 */
+
+		if (DISPLAY_VER(dev_priv) >= 14) {
+			/*
+			 * On versions 14 and up, only the first
+			 * scaler supports a vertical scaling factor
+			 * of more than 1.0, while a horizontal
+			 * scaling factor of 3.0 is supported.
+			 */
+			max_hscale = 0x30000 - 1;
+			if (*scaler_id == 0)
+				max_vscale = 0x30000 - 1;
+			else
+				max_vscale = 0x10000;
+
+		} else if (DISPLAY_VER(dev_priv) >= 10 ||
+			   !intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier)) {
+			max_hscale = 0x30000 - 1;
+			max_vscale = 0x30000 - 1;
+		} else {
+			max_hscale = 0x20000 - 1;
+			max_vscale = 0x20000 - 1;
+		}
+
+		/*
+		 * FIXME: We should change the if-else block above to
+		 * support HQ vs dynamic scaler properly.
+		 */
+
+		/* Check if required scaling is within limits */
+		hscale = drm_rect_calc_hscale(src, dst, 1, max_hscale);
+		vscale = drm_rect_calc_vscale(src, dst, 1, max_vscale);
+
+		if (hscale < 0 || vscale < 0) {
+			drm_dbg_kms(&dev_priv->drm,
+				    "Scaler %d doesn't support required plane scaling\n",
+				    *scaler_id);
+			drm_rect_debug_print("src: ", src, true);
+			drm_rect_debug_print("dst: ", dst, false);
+
+			return -EINVAL;
+		}
+	}
+
 	drm_dbg_kms(&dev_priv->drm, "Attached scaler id %u.%u to %s:%d\n",
 		    intel_crtc->pipe, *scaler_id, name, idx);
 	scaler_state->scalers[*scaler_id].mode = mode;
+
+	return 0;
 }
 
 /**
@@ -429,7 +492,7 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
 	for (i = 0; i < sizeof(scaler_state->scaler_users) * 8; i++) {
 		int *scaler_id;
 		const char *name;
-		int idx;
+		int idx, ret;
 
 		/* skip if scaler not required */
 		if (!(scaler_state->scaler_users & (1 << i)))
@@ -486,9 +549,11 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
 			scaler_id = &plane_state->scaler_id;
 		}
 
-		intel_atomic_setup_scaler(scaler_state, num_scalers_need,
-					  intel_crtc, name, idx,
-					  plane_state, scaler_id);
+		ret = intel_atomic_setup_scaler(scaler_state, num_scalers_need,
+						intel_crtc, name, idx,
+						plane_state, scaler_id);
+		if (ret < 0)
+			return ret;
 	}
 
 	return 0;
-- 
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