From: jsg <jsg@openbsd.org>
Date: Tue, 13 Jun 2023 03:43:25 +0000 (+0000)
Subject: drm/i915: Check pipe source size when using skl+ scalers
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=1dc0bf3b60cac3897ab2475fc072ccb3d93f9fa6;p=openbsd

drm/i915: Check pipe source size when using skl+ scalers

From Ville Syrjala
74a03d3c8d895a7d137bb4be8e40cae886f5d973 in linux-6.1.y/6.1.29
d944eafed618a8507270b324ad9d5405bb7f0b3e in mainline linux
---

diff --git a/sys/dev/pci/drm/i915/display/skl_scaler.c b/sys/dev/pci/drm/i915/display/skl_scaler.c
index e6ec5ed0d00..90f42f63128 100644
--- a/sys/dev/pci/drm/i915/display/skl_scaler.c
+++ b/sys/dev/pci/drm/i915/display/skl_scaler.c
@@ -105,6 +105,8 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->hw.adjusted_mode;
+	int pipe_src_w = drm_rect_width(&crtc_state->pipe_src);
+	int pipe_src_h = drm_rect_height(&crtc_state->pipe_src);
 	int min_src_w, min_src_h, min_dst_w, min_dst_h;
 	int max_src_w, max_src_h, max_dst_w, max_dst_h;
 
@@ -196,6 +198,21 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
 		return -EINVAL;
 	}
 
+	/*
+	 * The pipe scaler does not use all the bits of PIPESRC, at least
+	 * on the earlier platforms. So even when we're scaling a plane
+	 * the *pipe* source size must not be too large. For simplicity
+	 * we assume the limits match the scaler source size limits. Might
+	 * not be 100% accurate on all platforms, but good enough for now.
+	 */
+	if (pipe_src_w > max_src_w || pipe_src_h > max_src_h) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "scaler_user index %u.%u: pipe src size %ux%u "
+			    "is out of scaler range\n",
+			    crtc->pipe, scaler_user, pipe_src_w, pipe_src_h);
+		return -EINVAL;
+	}
+
 	/* mark this plane as a scaler user in crtc_state */
 	scaler_state->scaler_users |= (1 << scaler_user);
 	drm_dbg_kms(&dev_priv->drm, "scaler_user index %u.%u: "