drm/amdgpu_dm: Convert to atomic_create_state

The plane reset implementation creates a custom state
subclass, but only initializes a pristine state without resetting any
hardware. This is equivalent to what atomic_create_state expects.
Convert to it.

The conversion was done using the following Coccinelle semantic patch:

@@
identifier funcs;
symbol drm_atomic_helper_plane_reset;
symbol drm_atomic_helper_plane_create_state;
@@

struct drm_plane_funcs funcs = {
  ...,
- .reset = drm_atomic_helper_plane_reset,
+ .atomic_create_state = drm_atomic_helper_plane_create_state,
  ...,
};

@match_struct_reset@
identifier funcs, reset_func;
@@
struct drm_plane_funcs funcs = {
    ...,
    .reset = reset_func,
    ...,
};

@reset_uses_helpers depends on match_struct_reset@
identifier match_struct_reset.reset_func;
@@

 void reset_func(...)
 {
 	<+...
(
 	__drm_atomic_helper_plane_reset(...);
|
	__drm_gem_reset_shadow_plane(...);
)
 	...+>
 }

@match_struct_destroy@
identifier funcs, destroy_func;
@@
struct drm_plane_funcs funcs = {
    ...,
    .atomic_destroy_state = destroy_func,
    ...,
};

@script:python renamed_func@
old_name << match_struct_reset.reset_func;
new_name;
@@
if old_name.endswith("_reset"):
    coccinelle.new_name = old_name.replace("_reset", "_create_state")
else:
    coccinelle.new_name = old_name

@update_struct depends on match_struct_reset && reset_uses_helpers@
identifier match_struct_reset.funcs, match_struct_reset.reset_func;
identifier renamed_func.new_name;
@@
struct drm_plane_funcs funcs = {
    ...,
-   .reset = reset_func,
+   .atomic_create_state = new_name,
    ...,
};

@drop_destroy depends on update_struct && match_struct_destroy@
identifier match_struct_reset.reset_func;
identifier match_struct_destroy.destroy_func;
identifier container_func;
identifier P;
symbol drm_atomic_helper_plane_destroy_state;
symbol __drm_atomic_helper_plane_destroy_state;
@@

 void reset_func(struct drm_plane *P)
 {
 	...
(
-	if (P->state) {
- 		<+...
(
-		drm_atomic_helper_plane_destroy_state(P, P->state);
|
-		__drm_atomic_helper_plane_destroy_state(P->state);
|
-		P->funcs->atomic_destroy_state(P, P->state);
|
-		destroy_func(P, P->state);
)
- 		...+>
- 	}
|
-	drm_WARN_ON_ONCE(P->dev, P->state);
|
-	WARN_ON(P->state);
)
 	...
(
-	kfree(P->state);
|
-	kfree(container_func(P->state));
|
 	// kfree is optional
)
(
-	P->state = NULL;
|
 	// plane->state clearing is optional
)
 	...
 }

@drop_destroy_mtk depends on update_struct@
identifier P;
symbol __drm_atomic_helper_plane_destroy_state;
symbol to_mtk_plane_state;
@@

 void mtk_plane_reset(struct drm_plane *P)
 {
 	...
-	if (P->state) {
-		__drm_atomic_helper_plane_destroy_state(P->state);
-		...
-	} else {
 		...
-	}
 	...
 }

@transform_nv50_wndw depends on update_struct@
identifier S;
@@

 void nv50_wndw_reset(...)
 {
 	...
-	if (WARN_ON(!(S = kzalloc_obj(*S))))
+	S = kzalloc_obj(*S);
+	if (WARN_ON(!S))
 		return;
 	...
 }

@transform_kzalloc depends on update_struct@
identifier match_struct_reset.reset_func;
identifier P, S;
statement ST;
statement list STL;
@@

 void reset_func(struct drm_plane *P)
 {
 	<...
 	S = kzalloc_obj(*S);
(
-	if (S)
-	{
-		STL
-	}
+	if (!S) return;
+
+	STL
|
-	if (S) ST
+	if (!S) return;
+
+	ST
)
	...>
 }

@transform_body depends on update_struct@
identifier match_struct_reset.reset_func;
identifier renamed_func.new_name;
identifier S, P;
expression PS;
@@
- void reset_func(struct drm_plane *P)
+ struct drm_plane_state *new_name(struct drm_plane *P)
{
	...
 	S = kzalloc_obj(*S);
	...
(
 	if (!S) {
		...
-		return;
+		return ERR_PTR(-ENOMEM);
 	}
|
 	if (WARN_ON(!S)) {
		...
-		return;
+		return ERR_PTR(-ENOMEM);
 	}
|
 	if (S == NULL) {
 		...
-		return;
+		return ERR_PTR(-ENOMEM);
 	}
)
	...
(
-	__drm_atomic_helper_plane_reset(P, PS);
+	__drm_atomic_helper_plane_state_init(PS, P);
|
-	__drm_gem_reset_shadow_plane(P, PS);
+	__drm_gem_shadow_plane_state_init(P, PS);
)
	...
}

@update_early_return depends on update_struct@
identifier match_struct_reset.reset_func;
identifier renamed_func.new_name;
identifier P;
expression PS;
@@
 struct drm_plane_state *new_name(struct drm_plane *P)
{
	<+...
-	return;
+	return ERR_PTR(-EINVAL);
	...+>
}

@update_return_plane depends on update_struct@
identifier match_struct_reset.reset_func;
identifier renamed_func.new_name;
identifier P;
expression PS;
@@
 struct drm_plane_state *new_name(struct drm_plane *P)
{
	...
 	__drm_atomic_helper_plane_state_init(PS, P);
	...
+
+	return PS;
}

@update_return_shadow depends on update_struct@
identifier renamed_func.new_name;
identifier P;
expression PS;
@@
 struct drm_plane_state *new_name(struct drm_plane *P)
{
	...
 	__drm_gem_shadow_plane_state_init(P, PS);
	...
+
+	return &PS->base;
}

Reviewed-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/20260908-drm-no-more-plane-reset-v4-26-a31b3fcfc989@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c

@@ -1788,24 +1788,23 @@ static const struct drm_plane_helper_funcs dm_primary_plane_helper_funcs = {
 	.panic_flush = amdgpu_dm_plane_panic_flush,
 };
 
-STATIC_IFN_KUNIT void amdgpu_dm_plane_drm_plane_reset(struct drm_plane *plane)
+STATIC_IFN_KUNIT struct drm_plane_state *amdgpu_dm_plane_drm_plane_create_state(struct drm_plane *plane)
 {
 	struct dm_plane_state *amdgpu_state;
 
 	amdgpu_state = kzalloc_obj(*amdgpu_state);
 	if (!amdgpu_state)
-		return;
+		return ERR_PTR(-ENOMEM);
 
-	if (plane->state)
+	__drm_atomic_helper_plane_state_init(&amdgpu_state->base, plane);
-		plane->funcs->atomic_destroy_state(plane, plane->state);
-
-	__drm_atomic_helper_plane_reset(plane, &amdgpu_state->base);
 	amdgpu_state->degamma_tf = AMDGPU_TRANSFER_FUNCTION_DEFAULT;
 	amdgpu_state->hdr_mult = AMDGPU_HDR_MULT_DEFAULT;
 	amdgpu_state->shaper_tf = AMDGPU_TRANSFER_FUNCTION_DEFAULT;
 	amdgpu_state->blend_tf = AMDGPU_TRANSFER_FUNCTION_DEFAULT;
+
+	return &amdgpu_state->base;
 }
-EXPORT_IF_KUNIT(amdgpu_dm_plane_drm_plane_reset);
+EXPORT_IF_KUNIT(amdgpu_dm_plane_drm_plane_create_state);
 
 STATIC_IFN_KUNIT struct drm_plane_state *
 amdgpu_dm_plane_drm_plane_duplicate_state(struct drm_plane *plane)
@@ -2168,7 +2167,7 @@ static const struct drm_plane_funcs dm_plane_funcs = {
 	.update_plane	= drm_atomic_helper_update_plane,
 	.disable_plane	= drm_atomic_helper_disable_plane,
 	.destroy	= drm_plane_helper_destroy,
-	.reset = amdgpu_dm_plane_drm_plane_reset,
+	.atomic_create_state = amdgpu_dm_plane_drm_plane_create_state,
 	.atomic_duplicate_state = amdgpu_dm_plane_drm_plane_duplicate_state,
 	.atomic_destroy_state = amdgpu_dm_plane_drm_plane_destroy_state,
 	.format_mod_supported = amdgpu_dm_plane_format_mod_supported,
@@ -2303,9 +2302,16 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
 		return res;
 #endif
 
-	/* Create (reset) the plane state */
+	/* Create the plane state */
-	if (plane->funcs->reset)
+	if (plane->funcs->atomic_create_state) {
-		plane->funcs->reset(plane);
+		struct drm_plane_state *plane_state;
+
+		plane_state = plane->funcs->atomic_create_state(plane);
+		if (IS_ERR(plane_state))
+			return PTR_ERR(plane_state);
+
+		plane->state = plane_state;
+	}
 
 	return 0;
 }

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.h

@@ -117,7 +117,7 @@ int amdgpu_dm_plane_atomic_async_check(struct drm_plane *plane,
 int amdgpu_dm_plane_atomic_check(struct drm_plane *plane,
 				 struct drm_atomic_commit *state);
 void amdgpu_dm_plane_panic_flush(struct drm_plane *plane);
-void amdgpu_dm_plane_drm_plane_reset(struct drm_plane *plane);
+struct drm_plane_state *amdgpu_dm_plane_drm_plane_create_state(struct drm_plane *plane);
 struct drm_plane_state *amdgpu_dm_plane_drm_plane_duplicate_state(struct drm_plane *plane);
 void amdgpu_dm_plane_drm_plane_destroy_state(struct drm_plane *plane,
 					     struct drm_plane_state *state);

drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_plane_test.c

@@ -2924,14 +2924,14 @@ static const struct drm_plane_funcs dm_test_plane_reset_funcs = {
 };
 
 /**
- * dm_test_plane_reset_initializes_state() - Verify reset installs default state.
+ * dm_test_plane_create_state_initializes_state() - Verify create_state allocates default state.
  * @test: KUnit test context.
  *
- * Verify amdgpu_dm_plane_drm_plane_reset() destroys the existing plane state,
+ * Verify amdgpu_dm_plane_drm_plane_create_state() allocates a fresh
- * allocates a fresh dm_plane_state, and initializes the AMD-specific transfer
+ * dm_plane_state, and initializes the AMD-specific transfer function and HDR
- * function and HDR multiplier defaults.
+ * multiplier defaults.
  */
-static void dm_test_plane_reset_initializes_state(struct kunit *test)
+static void dm_test_plane_create_state_initializes_state(struct kunit *test)
 {
 	struct dm_plane_state *old_state;
 	struct dm_plane_state *new_state;
@@ -2940,20 +2940,12 @@ static void dm_test_plane_reset_initializes_state(struct kunit *test)
 	plane = kunit_kzalloc(test, sizeof(*plane), GFP_KERNEL);
 	KUNIT_ASSERT_NOT_NULL(test, plane);
 
-	/*
-	 * Provide an existing state plus a funcs table so reset exercises the
-	 * destroy-existing-state path. The destroy hook frees this state, so it
-	 * must be a plain (non-KUnit-managed) allocation.
-	 */
-	old_state = kzalloc_obj(*old_state);
-	KUNIT_ASSERT_NOT_NULL(test, old_state);
 	plane->funcs = &dm_test_plane_reset_funcs;
-	plane->state = &old_state->base;
 
-	amdgpu_dm_plane_drm_plane_reset(plane);
+	plane_state = amdgpu_dm_plane_drm_plane_create_state(plane);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, plane_state);
 
-	KUNIT_ASSERT_NOT_NULL(test, plane->state);
+	new_state = to_dm_plane_state(plane_state);
-	new_state = to_dm_plane_state(plane->state);
 	KUNIT_EXPECT_EQ(test, new_state->degamma_tf, AMDGPU_TRANSFER_FUNCTION_DEFAULT);
 	KUNIT_EXPECT_EQ(test, new_state->hdr_mult, AMDGPU_HDR_MULT_DEFAULT);
 	KUNIT_EXPECT_EQ(test, new_state->shaper_tf, AMDGPU_TRANSFER_FUNCTION_DEFAULT);
@@ -3098,8 +3090,8 @@ static struct kunit_case amdgpu_dm_plane_test_cases[] = {
 	KUNIT_CASE(dm_test_atomic_check_scaling_failure),
 	/* amdgpu_dm_plane_panic_flush() */
 	KUNIT_CASE(dm_test_panic_flush_no_dc_state),
-	/* amdgpu_dm_plane_drm_plane_reset() */
+	/* amdgpu_dm_plane_drm_plane_create_state() */
-	KUNIT_CASE(dm_test_plane_reset_initializes_state),
+	KUNIT_CASE(dm_test_plane_create_state_initializes_state),
 	/* amdgpu_dm_plane_drm_plane_duplicate_state() */
 	KUNIT_CASE(dm_test_plane_duplicate_state_copies_fields),
 	/* amdgpu_dm_plane_drm_plane_destroy_state() */