3 files changed, 39 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c
index d30374df67f0..e3e69e6cef65 100644
--- a/drivers/gpu/drm/i915/display/i9xx_plane.c
+++ b/drivers/gpu/drm/i915/display/i9xx_plane.c
@@ -256,6 +256,33 @@ int i9xx_check_plane_surface(struct intel_plane_state *plane_state)
 		offset = 0;
 
 	/*
+	 * When using an X-tiled surface the plane starts to
+	 * misbehave if the x offset + width exceeds the stride.
+	 * hsw/bdw: underrun galore
+	 * ilk/snb/ivb: wrap to the next tile row mid scanout
+	 * i965/g4x: so far appear immune to this
+	 * vlv/chv: TODO check
+	 *
+	 * Linear surfaces seem to work just fine, even on hsw/bdw
+	 * despite them not using the linear offset anymore.
+	 */
+	if (INTEL_GEN(dev_priv) >= 4 && fb->modifier == I915_FORMAT_MOD_X_TILED) {
+		u32 alignment = intel_surf_alignment(fb, 0);
+		int cpp = fb->format->cpp[0];
+
+		while ((src_x + src_w) * cpp > plane_state->color_plane[0].stride) {
+			if (offset == 0) {
+				drm_dbg_kms(&dev_priv->drm,
+					    "Unable to find suitable display surface offset due to X-tiling\n");
+				return -EINVAL;
+			}
+
+			offset = intel_plane_adjust_aligned_offset(&src_x, &src_y, plane_state, 0,
+								   offset, offset - alignment);
+		}
+	}
+
+	/*
 	 * Put the final coordinates back so that the src
 	 * coordinate checks will see the right values.
 	 */
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 9843a0f202a0..7ea1e5b487b6 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -1322,8 +1322,8 @@ static bool has_async_flips(struct drm_i915_private *i915)
 	return INTEL_GEN(i915) >= 5;
 }
 
-static unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
-					 int color_plane)
+unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
+				  int color_plane)
 {
 	struct drm_i915_private *dev_priv = to_i915(fb->dev);
 
@@ -1590,10 +1590,10 @@ static u32 intel_adjust_aligned_offset(int *x, int *y,
  * Adjust the tile offset by moving the difference into
  * the x/y offsets.
  */
-static u32 intel_plane_adjust_aligned_offset(int *x, int *y,
-					     const struct intel_plane_state *state,
-					     int color_plane,
-					     u32 old_offset, u32 new_offset)
+u32 intel_plane_adjust_aligned_offset(int *x, int *y,
+				      const struct intel_plane_state *state,
+				      int color_plane,
+				      u32 old_offset, u32 new_offset)
 {
 	return intel_adjust_aligned_offset(x, y, state->hw.fb, color_plane,
 					   state->hw.rotation,
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index 64ffa34544a7..76f8a805b0a3 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -653,6 +653,12 @@ void intel_plane_unpin_fb(struct intel_plane_state *old_plane_state);
 struct intel_encoder *
 intel_get_crtc_new_encoder(const struct intel_atomic_state *state,
 			   const struct intel_crtc_state *crtc_state);
+unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
+				  int color_plane);
+u32 intel_plane_adjust_aligned_offset(int *x, int *y,
+				      const struct intel_plane_state *state,
+				      int color_plane,
+				      u32 old_offset, u32 new_offset);
 
 /* modesetting */
 void intel_modeset_init_hw(struct drm_i915_private *i915);