drm/i915: Align PLANE_SURF to 16k on ADL for async flips

On ADL async flips apparently generate DMAR and GGTT faults
(with accompanying visual glitches) unless PLANE_SURF is
aligned to at least 16k. Bump up the alignment to 16k.

TODO: analyze things better to figure out what is really
      going on here
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240430095639.26390-2-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_dpt.c

@@ -121,7 +121,8 @@ static void dpt_cleanup(struct i915_address_space *vm)
 	i915_gem_object_put(dpt->obj);
 }
 
-struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
+struct i915_vma *intel_dpt_pin(struct i915_address_space *vm,
+			       unsigned int alignment)
 {
 	struct drm_i915_private *i915 = vm->i915;
 	struct i915_dpt *dpt = i915_vm_to_dpt(vm);
@@ -143,8 +144,8 @@ struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
 		if (err)
 			continue;
 
-		vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0, 4096,
-						  pin_flags);
+		vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0,
+						  alignment, pin_flags);
 		if (IS_ERR(vma)) {
 			err = PTR_ERR(vma);
 			continue;

drivers/gpu/drm/i915/display/intel_dpt.h

@@ -13,7 +13,8 @@ struct i915_vma;
 struct intel_framebuffer;
 
 void intel_dpt_destroy(struct i915_address_space *vm);
-struct i915_vma *intel_dpt_pin(struct i915_address_space *vm);
+struct i915_vma *intel_dpt_pin(struct i915_address_space *vm,
+			       unsigned int alignment);
 void intel_dpt_unpin(struct i915_address_space *vm);
 void intel_dpt_suspend(struct drm_i915_private *i915);
 void intel_dpt_resume(struct drm_i915_private *i915);

drivers/gpu/drm/i915/display/intel_fb.c

@@ -805,8 +805,23 @@ unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
 {
 	struct drm_i915_private *dev_priv = to_i915(fb->dev);
 
-	if (intel_fb_uses_dpt(fb))
+	if (intel_fb_uses_dpt(fb)) {
+		/* AUX_DIST needs only 4K alignment */
+		if (intel_fb_is_ccs_aux_plane(fb, color_plane))
+			return 512 * 4096;
+
+		/*
+		 * FIXME ADL sees GGTT/DMAR faults with async
+		 * flips unless we align to 16k at least.
+		 * Figure out what's going on here...
+		 */
+		if (IS_ALDERLAKE_P(dev_priv) &&
+		    !intel_fb_is_ccs_modifier(fb->modifier) &&
+		    HAS_ASYNC_FLIPS(dev_priv))
+			return 512 * 16 * 1024;
+
 		return 512 * 4096;
+	}
 
 	/* AUX_DIST needs only 4K alignment */
 	if (intel_fb_is_ccs_aux_plane(fb, color_plane))

drivers/gpu/drm/i915/display/intel_fb_pin.c

@@ -19,6 +19,7 @@
 static struct i915_vma *
 intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
 		     const struct i915_gtt_view *view,
+		     unsigned int alignment,
 		     bool uses_fence,
 		     unsigned long *out_flags,
 		     struct i915_address_space *vm)
@@ -28,7 +29,6 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	struct i915_gem_ww_ctx ww;
 	struct i915_vma *vma;
-	u32 alignment;
 	int ret;
 
 	/*
@@ -41,8 +41,6 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
 	if (WARN_ON(!i915_gem_object_is_framebuffer(obj)))
 		return ERR_PTR(-EINVAL);
 
-	alignment = 4096 * 512;
-
 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
 
 	for_i915_gem_ww(&ww, ret, true) {
@@ -267,14 +265,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
 				i915_gem_object_get_dma_address(intel_fb_obj(fb), 0);
 	} else {
 		struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
+		unsigned int alignment = intel_surf_alignment(fb, 0);
 
-		vma = intel_dpt_pin(intel_fb->dpt_vm);
+		vma = intel_dpt_pin(intel_fb->dpt_vm, alignment / 512);
 		if (IS_ERR(vma))
 			return PTR_ERR(vma);
 
 		plane_state->ggtt_vma = vma;
 
-		vma = intel_pin_fb_obj_dpt(fb, &plane_state->view.gtt, false,
+		vma = intel_pin_fb_obj_dpt(fb, &plane_state->view.gtt,
+					   alignment, false,
 					   &plane_state->flags, intel_fb->dpt_vm);
 		if (IS_ERR(vma)) {
 			intel_dpt_unpin(intel_fb->dpt_vm);