[PATCH 07/13] drm/vkms: Allow to configure multiple planes

José Expósito posted 13 patches 1 year ago
There is a newer version of this series
[PATCH 07/13] drm/vkms: Allow to configure multiple planes
Posted by José Expósito 1 year ago
Add a list of planes to vkms_config and create as many planes as
configured during output initialization.

For backwards compatibility, add one primary plane and, if configured,
one cursor plane and NUM_OVERLAY_PLANES planes to the default
configuration.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c | 133 +++++++++++++++-
 drivers/gpu/drm/vkms/vkms_config.c            | 149 +++++++++++++++++-
 drivers/gpu/drm/vkms/vkms_config.h            |  78 ++++++++-
 drivers/gpu/drm/vkms/vkms_output.c            |  67 ++++----
 4 files changed, 386 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index 66c2c6cb4a0e..7d9cb3956741 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -24,6 +24,10 @@ static void vkms_config_test_empty_config(struct kunit *test)
 	dev_name = NULL;
 	KUNIT_EXPECT_STREQ(test, vkms_config_get_device_name(config), "test");
 
+	KUNIT_EXPECT_TRUE(test, list_empty(&config->planes));
+
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
 	vkms_config_destroy(config);
 }
 
@@ -44,16 +48,138 @@ static void vkms_config_test_default_config(struct kunit *test)
 {
 	const struct default_config_case *params = test->param_value;
 	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+	int n_primaries = 0;
+	int n_cursors = 0;
+	int n_overlays = 0;
 
 	config = vkms_config_default_create(params->enable_cursor,
 					    params->enable_writeback,
 					    params->enable_overlay);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
 
-	KUNIT_EXPECT_EQ(test, config->cursor, params->enable_cursor);
 	KUNIT_EXPECT_EQ(test, config->writeback, params->enable_writeback);
-	KUNIT_EXPECT_EQ(test, config->overlay, params->enable_overlay);
 
+	/* Planes */
+	list_for_each_entry(plane_cfg, &config->planes, link) {
+		switch (vkms_config_plane_get_type(plane_cfg)) {
+		case DRM_PLANE_TYPE_PRIMARY:
+			n_primaries++;
+			break;
+		case DRM_PLANE_TYPE_CURSOR:
+			n_cursors++;
+			break;
+		case DRM_PLANE_TYPE_OVERLAY:
+			n_overlays++;
+			break;
+		default:
+			KUNIT_FAIL_AND_ABORT(test, "Unknown plane type");
+		}
+	}
+	KUNIT_EXPECT_EQ(test, n_primaries, 1);
+	KUNIT_EXPECT_EQ(test, n_cursors, params->enable_cursor ? 1 : 0);
+	KUNIT_EXPECT_EQ(test, n_overlays, params->enable_overlay ? 8 : 0);
+
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
+static void vkms_config_test_get_planes(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg1, *plane_cfg2;
+	struct vkms_config_plane **array;
+	size_t length;
+
+	config = vkms_config_create("test");
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	array = vkms_config_get_planes(config, &length);
+	KUNIT_ASSERT_EQ(test, length, 0);
+	KUNIT_ASSERT_NULL(test, array);
+
+	plane_cfg1 = vkms_config_add_plane(config);
+	array = vkms_config_get_planes(config, &length);
+	KUNIT_ASSERT_EQ(test, length, 1);
+	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
+	kfree(array);
+
+	plane_cfg2 = vkms_config_add_plane(config);
+	array = vkms_config_get_planes(config, &length);
+	KUNIT_ASSERT_EQ(test, length, 2);
+	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
+	KUNIT_ASSERT_PTR_EQ(test, array[1], plane_cfg2);
+	kfree(array);
+
+	vkms_config_destroy_plane(plane_cfg1);
+	array = vkms_config_get_planes(config, &length);
+	KUNIT_ASSERT_EQ(test, length, 1);
+	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg2);
+	kfree(array);
+
+	vkms_config_destroy(config);
+}
+
+static void vkms_config_test_valid_plane_number(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+	int n;
+
+	config = vkms_config_default_create(false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	/* Invalid: No planes */
+	plane_cfg = list_first_entry(&config->planes, typeof(*plane_cfg), link);
+	vkms_config_destroy_plane(plane_cfg);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Invalid: Too many planes */
+	for (n = 0; n <= 32; n++)
+		vkms_config_add_plane(config);
+
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
+static void vkms_config_test_valid_plane_type(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+
+	config = vkms_config_default_create(false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	plane_cfg = list_first_entry(&config->planes, typeof(*plane_cfg), link);
+	vkms_config_destroy_plane(plane_cfg);
+
+	/* Invalid: No primary plane */
+	plane_cfg = vkms_config_add_plane(config);
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Invalid: Multiple primary planes */
+	plane_cfg = vkms_config_add_plane(config);
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_PRIMARY);
+	plane_cfg = vkms_config_add_plane(config);
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_PRIMARY);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid: One primary plane */
+	vkms_config_destroy_plane(plane_cfg);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid: Multiple cursor planes */
+	plane_cfg = vkms_config_add_plane(config);
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_CURSOR);
+	plane_cfg = vkms_config_add_plane(config);
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_CURSOR);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid: One primary and one cursor plane */
+	vkms_config_destroy_plane(plane_cfg);
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
 
 	vkms_config_destroy(config);
@@ -63,6 +189,9 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_empty_config),
 	KUNIT_CASE_PARAM(vkms_config_test_default_config,
 			 default_config_gen_params),
+	KUNIT_CASE(vkms_config_test_get_planes),
+	KUNIT_CASE(vkms_config_test_valid_plane_number),
+	KUNIT_CASE(vkms_config_test_valid_plane_type),
 	{}
 };
 
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 67f71d29596e..a5a77612645f 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -21,6 +21,8 @@ struct vkms_config *vkms_config_create(const char *dev_name)
 		return ERR_PTR(-ENOMEM);
 	}
 
+	INIT_LIST_HEAD(&config->planes);
+
 	return config;
 }
 
@@ -29,26 +31,139 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
 					       bool enable_overlay)
 {
 	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+	int n;
 
 	config = vkms_config_create(DEFAULT_DEVICE_NAME);
 	if (IS_ERR(config))
 		return config;
 
-	config->cursor = enable_cursor;
 	config->writeback = enable_writeback;
-	config->overlay = enable_overlay;
+
+	plane_cfg = vkms_config_add_plane(config);
+	if (IS_ERR(plane_cfg))
+		goto err_alloc;
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_PRIMARY);
+
+	if (enable_overlay) {
+		for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
+			plane_cfg = vkms_config_add_plane(config);
+			if (IS_ERR(plane_cfg))
+				goto err_alloc;
+			vkms_config_plane_set_type(plane_cfg,
+						   DRM_PLANE_TYPE_OVERLAY);
+		}
+	}
+
+	if (enable_cursor) {
+		plane_cfg = vkms_config_add_plane(config);
+		if (IS_ERR(plane_cfg))
+			goto err_alloc;
+		vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_CURSOR);
+	}
 
 	return config;
+
+err_alloc:
+	vkms_config_destroy(config);
+	return ERR_PTR(-ENOMEM);
 }
 
 void vkms_config_destroy(struct vkms_config *config)
 {
+	struct vkms_config_plane *plane_cfg, *plane_tmp;
+
+	list_for_each_entry_safe(plane_cfg, plane_tmp, &config->planes, link)
+		vkms_config_destroy_plane(plane_cfg);
+
 	kfree_const(config->dev_name);
 	kfree(config);
 }
 
+struct vkms_config_plane **vkms_config_get_planes(const struct vkms_config *config,
+						  size_t *out_length)
+{
+	struct vkms_config_plane **array;
+	struct vkms_config_plane *plane_cfg;
+	size_t length;
+	int n = 0;
+
+	length = list_count_nodes((struct list_head *)&config->planes);
+	if (length == 0) {
+		*out_length = length;
+		return NULL;
+	}
+
+	array = kmalloc_array(length, sizeof(*array), GFP_KERNEL);
+	if (!array)
+		return ERR_PTR(-ENOMEM);
+
+	list_for_each_entry(plane_cfg, &config->planes, link) {
+		array[n] = plane_cfg;
+		n++;
+	}
+
+	*out_length = length;
+	return array;
+}
+
+static bool valid_plane_number(struct vkms_config *config)
+{
+	size_t n_planes;
+
+	n_planes = list_count_nodes(&config->planes);
+	if (n_planes <= 0 || n_planes >= 32) {
+		pr_err("The number of planes must be between 1 and 31\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool valid_plane_type(struct vkms_config *config)
+{
+	struct vkms_config_plane *plane_cfg;
+	bool has_primary_plane = false;
+	bool has_cursor_plane = false;
+
+	list_for_each_entry(plane_cfg, &config->planes, link) {
+		enum drm_plane_type type;
+
+		type = vkms_config_plane_get_type(plane_cfg);
+
+		if (type == DRM_PLANE_TYPE_PRIMARY) {
+			if (has_primary_plane) {
+				pr_err("Multiple primary planes\n");
+				return false;
+			}
+
+			has_primary_plane = true;
+		} else if (type == DRM_PLANE_TYPE_CURSOR) {
+			if (has_cursor_plane) {
+				pr_err("Multiple cursor planes\n");
+				return false;
+			}
+
+			has_cursor_plane = true;
+		}
+	}
+
+	if (!has_primary_plane) {
+		pr_err("Primary plane not found\n");
+		return false;
+	}
+
+	return true;
+}
+
 bool vkms_config_is_valid(struct vkms_config *config)
 {
+	if (!valid_plane_number(config))
+		return false;
+
+	if (!valid_plane_type(config))
+		return false;
+
 	return true;
 }
 
@@ -58,12 +173,17 @@ static int vkms_config_show(struct seq_file *m, void *data)
 	struct drm_device *dev = entry->dev;
 	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
 	const char *dev_name;
+	struct vkms_config_plane *plane_cfg;
 
 	dev_name = vkms_config_get_device_name((struct vkms_config *)vkmsdev->config);
 	seq_printf(m, "dev_name=%s\n", dev_name);
 	seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
-	seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
-	seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
+
+	list_for_each_entry(plane_cfg, &vkmsdev->config->planes, link) {
+		seq_puts(m, "plane:\n");
+		seq_printf(m, "\ttype=%d\n",
+			   vkms_config_plane_get_type(plane_cfg));
+	}
 
 	return 0;
 }
@@ -77,3 +197,24 @@ void vkms_config_register_debugfs(struct vkms_device *vkms_device)
 	drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
 			      ARRAY_SIZE(vkms_config_debugfs_list));
 }
+
+struct vkms_config_plane *vkms_config_add_plane(struct vkms_config *config)
+{
+	struct vkms_config_plane *plane_cfg;
+
+	plane_cfg = kzalloc(sizeof(*plane_cfg), GFP_KERNEL);
+	if (!plane_cfg)
+		return ERR_PTR(-ENOMEM);
+
+	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY);
+
+	list_add_tail(&plane_cfg->link, &config->planes);
+
+	return plane_cfg;
+}
+
+void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg)
+{
+	list_del(&plane_cfg->link);
+	kfree(plane_cfg);
+}
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 963f22b9b4bd..d9aeba1762d1 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -3,6 +3,7 @@
 #ifndef _VKMS_CONFIG_H_
 #define _VKMS_CONFIG_H_
 
+#include <linux/list.h>
 #include <linux/types.h>
 
 #include "vkms_drv.h"
@@ -12,18 +13,36 @@
  *
  * @dev_name: Name of the device
  * @writeback: If true, a writeback buffer can be attached to the CRTC
- * @cursor: If true, a cursor plane is created in the VKMS device
- * @overlay: If true, NUM_OVERLAY_PLANES will be created for the VKMS device
+ * @planes: List of planes configured for the device
  * @dev: Used to store the current VKMS device. Only set when the device is instantiated.
  */
 struct vkms_config {
 	const char *dev_name;
 	bool writeback;
-	bool cursor;
-	bool overlay;
+	struct list_head planes;
 	struct vkms_device *dev;
 };
 
+/**
+ * struct vkms_config_plane
+ *
+ * @link: Link to the others planes in vkms_config
+ * @type: Type of the plane. The creator of configuration needs to ensures that
+ *        at least one primary plane is present.
+ * @plane: Internal usage. This pointer should never be considered as valid.
+ *         It can be used to store a temporary reference to a VKMS plane during
+ *         device creation. This pointer is not managed by the configuration and
+ *         must be managed by other means.
+ */
+struct vkms_config_plane {
+	struct list_head link;
+
+	enum drm_plane_type type;
+
+	/* Internal usage */
+	struct vkms_plane *plane;
+};
+
 /**
  * vkms_config_create() - Create a new VKMS configuration
  * @dev_name: Name of the device
@@ -64,6 +83,19 @@ vkms_config_get_device_name(struct vkms_config *config)
 	return config->dev_name;
 }
 
+/**
+ * vkms_config_planes() - Return the array of planes of the device
+ * @config: Configuration to get the planes from
+ * @out_length: Length of the returned array
+ *
+ * Returns:
+ * A list of pointers to the configurations. On success, the caller is
+ * responsible to free the returned array, but not its contents. On error,
+ * it returns an error and @out_length is invalid.
+ */
+struct vkms_config_plane **vkms_config_get_planes(const struct vkms_config *config,
+						  size_t *out_length);
+
 /**
  * vkms_config_is_valid() - Validate a configuration
  * @config: Configuration to validate
@@ -81,4 +113,42 @@ bool vkms_config_is_valid(struct vkms_config *config);
  */
 void vkms_config_register_debugfs(struct vkms_device *vkms_device);
 
+/**
+ * vkms_config_add_plane() - Add a new plane configuration
+ * @config: Configuration to add the plane to
+ *
+ * Returns:
+ * The new plane configuration or an error. Call vkms_config_destroy_plane() to
+ * free the returned plane configuration.
+ */
+struct vkms_config_plane *vkms_config_add_plane(struct vkms_config *config);
+
+/**
+ * vkms_config_destroy_plane() - Remove and free a plane configuration
+ * @plane_cfg: Plane configuration to destroy
+ */
+void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg);
+
+/**
+ * vkms_config_plane_type() - Return the plane type
+ * @plane_cfg: Plane to get the type from
+ */
+static inline enum drm_plane_type
+vkms_config_plane_get_type(struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->type;
+}
+
+/**
+ * vkms_config_plane_set_type() - Set the plane type
+ * @plane_cfg: Plane to set the type to
+ * @type: New plane type
+ */
+static inline void
+vkms_config_plane_set_type(struct vkms_config_plane *plane_cfg,
+			   enum drm_plane_type type)
+{
+	plane_cfg->type = type;
+}
+
 #endif /* _VKMS_CONFIG_H_ */
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 068a7f87ecec..b2ae269e5827 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -11,61 +11,63 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 	struct vkms_connector *connector;
 	struct drm_encoder *encoder;
 	struct vkms_output *output;
-	struct vkms_plane *primary, *overlay, *cursor = NULL;
-	int ret;
+	struct vkms_plane *primary = NULL, *cursor = NULL;
+	struct vkms_config_plane **plane_cfgs = NULL;
+	size_t n_planes;
+	int ret = 0;
 	int writeback;
 	unsigned int n;
 
-	/*
-	 * Initialize used plane. One primary plane is required to perform the composition.
-	 *
-	 * The overlay and cursor planes are not mandatory, but can be used to perform complex
-	 * composition.
-	 */
-	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
-	if (IS_ERR(primary))
-		return PTR_ERR(primary);
+	plane_cfgs = vkms_config_get_planes(vkmsdev->config, &n_planes);
+	if (IS_ERR(plane_cfgs))
+		return PTR_ERR(plane_cfgs);
 
-	if (vkmsdev->config->cursor) {
-		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
-		if (IS_ERR(cursor))
-			return PTR_ERR(cursor);
+	for (n = 0; n < n_planes; n++) {
+		struct vkms_config_plane *plane_cfg;
+		enum drm_plane_type type;
+
+		plane_cfg = plane_cfgs[n];
+		type = vkms_config_plane_get_type(plane_cfg);
+
+		plane_cfg->plane = vkms_plane_init(vkmsdev, type);
+		if (IS_ERR(plane_cfg->plane)) {
+			DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n");
+			ret = PTR_ERR(plane_cfg->plane);
+			goto err_free;
+		}
+
+		if (type == DRM_PLANE_TYPE_PRIMARY)
+			primary = plane_cfg->plane;
+		else if (type == DRM_PLANE_TYPE_CURSOR)
+			cursor = plane_cfg->plane;
 	}
 
 	output = vkms_crtc_init(dev, &primary->base,
 				cursor ? &cursor->base : NULL);
 	if (IS_ERR(output)) {
 		DRM_ERROR("Failed to allocate CRTC\n");
-		return PTR_ERR(output);
-	}
-
-	if (vkmsdev->config->overlay) {
-		for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
-			overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY);
-			if (IS_ERR(overlay)) {
-				DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n");
-				return PTR_ERR(overlay);
-			}
-			overlay->base.possible_crtcs = drm_crtc_mask(&output->crtc);
-		}
+		ret = PTR_ERR(output);
+		goto err_free;
 	}
 
 	connector = vkms_connector_init(vkmsdev);
 	if (IS_ERR(connector)) {
 		DRM_ERROR("Failed to init connector\n");
-		return PTR_ERR(connector);
+		ret = PTR_ERR(connector);
+		goto err_free;
 	}
 
 	encoder = drmm_kzalloc(dev, sizeof(*encoder), GFP_KERNEL);
 	if (!encoder) {
 		DRM_ERROR("Failed to allocate encoder\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_free;
 	}
 	ret = drmm_encoder_init(dev, encoder, NULL,
 				DRM_MODE_ENCODER_VIRTUAL, NULL);
 	if (ret) {
 		DRM_ERROR("Failed to init encoder\n");
-		return ret;
+		goto err_free;
 	}
 	encoder->possible_crtcs = drm_crtc_mask(&output->crtc);
 
@@ -73,7 +75,7 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 	ret = drm_connector_attach_encoder(&connector->base, encoder);
 	if (ret) {
 		DRM_ERROR("Failed to attach connector to encoder\n");
-		return ret;
+		goto err_free;
 	}
 
 	/* Initialize the writeback component */
@@ -85,5 +87,8 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 
 	drm_mode_config_reset(dev);
 
+err_free:
+	kfree(plane_cfgs);
+
 	return ret;
 }
-- 
2.48.1

Re: [PATCH 07/13] drm/vkms: Allow to configure multiple planes
Posted by Louis Chauvet 1 year ago
On 29/01/25 - 12:00, José Expósito wrote:
> Add a list of planes to vkms_config and create as many planes as
> configured during output initialization.
> 
> For backwards compatibility, add one primary plane and, if configured,
> one cursor plane and NUM_OVERLAY_PLANES planes to the default
> configuration.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>

Co-developped-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>

[...]

> diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c

[...]

> +static void vkms_config_test_get_planes(struct kunit *test)
> +{
> +	struct vkms_config *config;
> +	struct vkms_config_plane *plane_cfg1, *plane_cfg2;
> +	struct vkms_config_plane **array;
> +	size_t length;
> +
> +	config = vkms_config_create("test");
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> +
> +	array = vkms_config_get_planes(config, &length);
> +	KUNIT_ASSERT_EQ(test, length, 0);
> +	KUNIT_ASSERT_NULL(test, array);
> +
> +	plane_cfg1 = vkms_config_add_plane(config);
> +	array = vkms_config_get_planes(config, &length);
> +	KUNIT_ASSERT_EQ(test, length, 1);
> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
> +	kfree(array);
> +
> +	plane_cfg2 = vkms_config_add_plane(config);
> +	array = vkms_config_get_planes(config, &length);
> +	KUNIT_ASSERT_EQ(test, length, 2);
> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
> +	KUNIT_ASSERT_PTR_EQ(test, array[1], plane_cfg2);
> +	kfree(array);
> +
> +	vkms_config_destroy_plane(plane_cfg1);
> +	array = vkms_config_get_planes(config, &length);
> +	KUNIT_ASSERT_EQ(test, length, 1);
> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg2);
> +	kfree(array);
> +
> +	vkms_config_destroy(config);
> +}

In this test I have the feeling that vkms_config_get_planes always returns 
a predictable order. It is maybe trivial here, but I would prefer to shows 
that the order is not stable, for example:

	bool plane_cfg1_found = false;
	bool plane_cfg2_found = false;

	vkms_config_for_each_plane(config, plane_cfg) {
		if (plane_cfg == plane_cfg1)
			plane_cfg1_found = true;
		else if (plane_cfg == plane_cfg2)
			plane_cfg2_found = true;
		else
			KUNIT_FAILS("Unexpected plane");
	}

	KUNIT_ASSERT(test, plane_cfg1_found);
	KUNIT_ASSERT(test, plane_cfg2_found);

[...]

> +static void vkms_config_test_valid_plane_number(struct kunit *test)
> +{
> +	struct vkms_config *config;
> +	struct vkms_config_plane *plane_cfg;
> +	int n;
> +
> +	config = vkms_config_default_create(false, false, false);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> +
> +	/* Invalid: No planes */
> +	plane_cfg = list_first_entry(&config->planes, typeof(*plane_cfg), link);
> +	vkms_config_destroy_plane(plane_cfg);
> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> +
> +	/* Invalid: Too many planes */
> +	for (n = 0; n <= 32; n++)
> +		vkms_config_add_plane(config);
> +
> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> +
> +	vkms_config_destroy(config);
> +}

For this function, the naming is a bit strange, it says 
"valid_plane_number", but you test only invalid plane number.

Can you rename it to vkms_config_test_invalid_plane_number?

[...]

> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c

[...]

> +struct vkms_config_plane **vkms_config_get_planes(const struct vkms_config *config,
> +						  size_t *out_length)
> +{
> +	struct vkms_config_plane **array;
> +	struct vkms_config_plane *plane_cfg;
> +	size_t length;
> +	int n = 0;
> +
> +	length = list_count_nodes((struct list_head *)&config->planes);
> +	if (length == 0) {
> +		*out_length = length;
> +		return NULL;
> +	}
> +
> +	array = kmalloc_array(length, sizeof(*array), GFP_KERNEL);
> +	if (!array)
> +		return ERR_PTR(-ENOMEM);
> +
> +	list_for_each_entry(plane_cfg, &config->planes, link) {
> +		array[n] = plane_cfg;
> +		n++;
> +	}
> +
> +	*out_length = length;
> +	return array;
> +}

To join the comment on the test, I am not a big fan of creating a new list 
to return to the caller, for three reasons:
- the caller needs to manage an other pointer;
- the caller needs to understand that the content of the array is only 
  valid if: the config is not freed, nobody else removed anything from the 
  planes;
- the caller may think this list always have the same order if he looks at 
  the tests.

I would prefer a simple macro to do an iteration over the config->planes 
list: (I did not test this macro, but you have this idea)

	#define vkms_config_iter_plane(config, plane_cfg) \
		list_for_each_entry((plane_cfg), &(config).planes, link)

This way:
- no new pointer to manage;
- if one day we have concurency issue, we just have to protect config, not 
  config+all the planes;
- there is no expected order.

[...]

>  bool vkms_config_is_valid(struct vkms_config *config)
>  {
> +	if (!valid_plane_number(config))
> +		return false;
> +
> +	if (!valid_plane_type(config))
> +		return false;
> +
>  	return true;
>  }

I really like the idea to split the validation function, way simpler!

[...]

> +void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg)
> +{
> +	list_del(&plane_cfg->link);
> +	kfree(plane_cfg);
> +}

I would prefer a "standard" function pair, i.e.: add/remove or 
create/destroy, not add/destroy.

For me it should be create/destroy, you create the plane by using a 
config, so it is clear it will be attached to it.

If you choose add/remove, you should explains in the documentation that 
remove is also doing kfree.

[...]

> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c

[...]

> @@ -11,61 +11,63 @@ int vkms_output_init(struct vkms_device *vkmsdev)
>  	struct vkms_connector *connector;
>  	struct drm_encoder *encoder;
>  	struct vkms_output *output;
> -	struct vkms_plane *primary, *overlay, *cursor = NULL;
> -	int ret;
> +	struct vkms_plane *primary = NULL, *cursor = NULL;
> +	struct vkms_config_plane **plane_cfgs = NULL;
> +	size_t n_planes;
> +	int ret = 0;
>  	int writeback;
>  	unsigned int n;

I think it could be interesting to have a vkms_config_is_valid call here. 
It will avoid raising DRM errors or create unexpected devices.

It will also garantee in a later patch that 
vkms_config_crtc_get_primary_plane is a valid pointer.

> -	/*
> -	 * Initialize used plane. One primary plane is required to perform the composition.
> -	 *
> -	 * The overlay and cursor planes are not mandatory, but can be used to perform complex
> -	 * composition.
> -	 */
> -	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
> -	if (IS_ERR(primary))
> -		return PTR_ERR(primary);
> +	plane_cfgs = vkms_config_get_planes(vkmsdev->config, &n_planes);
> +	if (IS_ERR(plane_cfgs))
> +		return PTR_ERR(plane_cfgs);

If you agree on the iterator implementation, this code could be simplified 
a lot.

> -	if (vkmsdev->config->cursor) {
> -		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
> -		if (IS_ERR(cursor))
> -			return PTR_ERR(cursor);
> +	for (n = 0; n < n_planes; n++) {
> +		struct vkms_config_plane *plane_cfg;
> +		enum drm_plane_type type;
> +
> +		plane_cfg = plane_cfgs[n];
> +		type = vkms_config_plane_get_type(plane_cfg);
> +
> +		plane_cfg->plane = vkms_plane_init(vkmsdev, type);

Can we pass plane_cfg in vkms_plane_init? This way we don't have to 
touch vkms_output_init when adding new vkms_config_plane members.

> +		if (IS_ERR(plane_cfg->plane)) {
> +			DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n");
> +			ret = PTR_ERR(plane_cfg->plane);
> +			goto err_free;
> +		}
> +
> +		if (type == DRM_PLANE_TYPE_PRIMARY)
> +			primary = plane_cfg->plane;
> +		else if (type == DRM_PLANE_TYPE_CURSOR)
> +			cursor = plane_cfg->plane;
>  	}

[...]
Re: [PATCH 07/13] drm/vkms: Allow to configure multiple planes
Posted by José Expósito 12 months ago
On Thu, Jan 30, 2025 at 02:48:19PM +0100, Louis Chauvet wrote:
> On 29/01/25 - 12:00, José Expósito wrote:
> > Add a list of planes to vkms_config and create as many planes as
> > configured during output initialization.
> > 
> > For backwards compatibility, add one primary plane and, if configured,
> > one cursor plane and NUM_OVERLAY_PLANES planes to the default
> > configuration.
> > 
> > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> 
> Co-developped-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> 
> [...]
> 
> > diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> 
> [...]
> 
> > +static void vkms_config_test_get_planes(struct kunit *test)
> > +{
> > +	struct vkms_config *config;
> > +	struct vkms_config_plane *plane_cfg1, *plane_cfg2;
> > +	struct vkms_config_plane **array;
> > +	size_t length;
> > +
> > +	config = vkms_config_create("test");
> > +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> > +
> > +	array = vkms_config_get_planes(config, &length);
> > +	KUNIT_ASSERT_EQ(test, length, 0);
> > +	KUNIT_ASSERT_NULL(test, array);
> > +
> > +	plane_cfg1 = vkms_config_add_plane(config);
> > +	array = vkms_config_get_planes(config, &length);
> > +	KUNIT_ASSERT_EQ(test, length, 1);
> > +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
> > +	kfree(array);
> > +
> > +	plane_cfg2 = vkms_config_add_plane(config);
> > +	array = vkms_config_get_planes(config, &length);
> > +	KUNIT_ASSERT_EQ(test, length, 2);
> > +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
> > +	KUNIT_ASSERT_PTR_EQ(test, array[1], plane_cfg2);
> > +	kfree(array);
> > +
> > +	vkms_config_destroy_plane(plane_cfg1);
> > +	array = vkms_config_get_planes(config, &length);
> > +	KUNIT_ASSERT_EQ(test, length, 1);
> > +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg2);
> > +	kfree(array);
> > +
> > +	vkms_config_destroy(config);
> > +}
> 
> In this test I have the feeling that vkms_config_get_planes always returns 
> a predictable order. It is maybe trivial here, but I would prefer to shows 
> that the order is not stable, for example:
> 
> 	bool plane_cfg1_found = false;
> 	bool plane_cfg2_found = false;
> 
> 	vkms_config_for_each_plane(config, plane_cfg) {
> 		if (plane_cfg == plane_cfg1)
> 			plane_cfg1_found = true;
> 		else if (plane_cfg == plane_cfg2)
> 			plane_cfg2_found = true;
> 		else
> 			KUNIT_FAILS("Unexpected plane");
> 	}
> 
> 	KUNIT_ASSERT(test, plane_cfg1_found);
> 	KUNIT_ASSERT(test, plane_cfg2_found);
> 
> [...]
> 
> > +static void vkms_config_test_valid_plane_number(struct kunit *test)
> > +{
> > +	struct vkms_config *config;
> > +	struct vkms_config_plane *plane_cfg;
> > +	int n;
> > +
> > +	config = vkms_config_default_create(false, false, false);
> > +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> > +
> > +	/* Invalid: No planes */
> > +	plane_cfg = list_first_entry(&config->planes, typeof(*plane_cfg), link);
> > +	vkms_config_destroy_plane(plane_cfg);
> > +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> > +
> > +	/* Invalid: Too many planes */
> > +	for (n = 0; n <= 32; n++)
> > +		vkms_config_add_plane(config);
> > +
> > +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> > +
> > +	vkms_config_destroy(config);
> > +}
> 
> For this function, the naming is a bit strange, it says 
> "valid_plane_number", but you test only invalid plane number.

The reason for this naming is that it tests the valid_plane_number()
function called by vkms_config_is_valid(). The applies for the other
valid_* tests.

However, I don't mind changing its name to so it reflects the test
rather than the tested function.

Changed in v2.

> 
> Can you rename it to vkms_config_test_invalid_plane_number?
> 
> [...]
> 
> > diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
> 
> [...]
> 
> > +struct vkms_config_plane **vkms_config_get_planes(const struct vkms_config *config,
> > +						  size_t *out_length)
> > +{
> > +	struct vkms_config_plane **array;
> > +	struct vkms_config_plane *plane_cfg;
> > +	size_t length;
> > +	int n = 0;
> > +
> > +	length = list_count_nodes((struct list_head *)&config->planes);
> > +	if (length == 0) {
> > +		*out_length = length;
> > +		return NULL;
> > +	}
> > +
> > +	array = kmalloc_array(length, sizeof(*array), GFP_KERNEL);
> > +	if (!array)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	list_for_each_entry(plane_cfg, &config->planes, link) {
> > +		array[n] = plane_cfg;
> > +		n++;
> > +	}
> > +
> > +	*out_length = length;
> > +	return array;
> > +}
> 
> To join the comment on the test, I am not a big fan of creating a new list 
> to return to the caller, for three reasons:
> - the caller needs to manage an other pointer;
> - the caller needs to understand that the content of the array is only 
>   valid if: the config is not freed, nobody else removed anything from the 
>   planes;
> - the caller may think this list always have the same order if he looks at 
>   the tests.
> 
> I would prefer a simple macro to do an iteration over the config->planes 
> list: (I did not test this macro, but you have this idea)
> 
> 	#define vkms_config_iter_plane(config, plane_cfg) \
> 		list_for_each_entry((plane_cfg), &(config).planes, link)
> 
> This way:
> - no new pointer to manage;
> - if one day we have concurency issue, we just have to protect config, not 
>   config+all the planes;
> - there is no expected order.
> 
> [...]
> 
> >  bool vkms_config_is_valid(struct vkms_config *config)
> >  {
> > +	if (!valid_plane_number(config))
> > +		return false;
> > +
> > +	if (!valid_plane_type(config))
> > +		return false;
> > +
> >  	return true;
> >  }
> 
> I really like the idea to split the validation function, way simpler!
> 
> [...]
> 
> > +void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg)
> > +{
> > +	list_del(&plane_cfg->link);
> > +	kfree(plane_cfg);
> > +}
> 
> I would prefer a "standard" function pair, i.e.: add/remove or 
> create/destroy, not add/destroy.
> 
> For me it should be create/destroy, you create the plane by using a 
> config, so it is clear it will be attached to it.
> 
> If you choose add/remove, you should explains in the documentation that 
> remove is also doing kfree.
> 
> [...]
> 
> > diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> 
> [...]
> 
> > @@ -11,61 +11,63 @@ int vkms_output_init(struct vkms_device *vkmsdev)
> >  	struct vkms_connector *connector;
> >  	struct drm_encoder *encoder;
> >  	struct vkms_output *output;
> > -	struct vkms_plane *primary, *overlay, *cursor = NULL;
> > -	int ret;
> > +	struct vkms_plane *primary = NULL, *cursor = NULL;
> > +	struct vkms_config_plane **plane_cfgs = NULL;
> > +	size_t n_planes;
> > +	int ret = 0;
> >  	int writeback;
> >  	unsigned int n;
> 
> I think it could be interesting to have a vkms_config_is_valid call here. 
> It will avoid raising DRM errors or create unexpected devices.
> 
> It will also garantee in a later patch that 
> vkms_config_crtc_get_primary_plane is a valid pointer.
> 
> > -	/*
> > -	 * Initialize used plane. One primary plane is required to perform the composition.
> > -	 *
> > -	 * The overlay and cursor planes are not mandatory, but can be used to perform complex
> > -	 * composition.
> > -	 */
> > -	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
> > -	if (IS_ERR(primary))
> > -		return PTR_ERR(primary);
> > +	plane_cfgs = vkms_config_get_planes(vkmsdev->config, &n_planes);
> > +	if (IS_ERR(plane_cfgs))
> > +		return PTR_ERR(plane_cfgs);
> 
> If you agree on the iterator implementation, this code could be simplified 
> a lot.
> 
> > -	if (vkmsdev->config->cursor) {
> > -		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
> > -		if (IS_ERR(cursor))
> > -			return PTR_ERR(cursor);
> > +	for (n = 0; n < n_planes; n++) {
> > +		struct vkms_config_plane *plane_cfg;
> > +		enum drm_plane_type type;
> > +
> > +		plane_cfg = plane_cfgs[n];
> > +		type = vkms_config_plane_get_type(plane_cfg);
> > +
> > +		plane_cfg->plane = vkms_plane_init(vkmsdev, type);
> 
> Can we pass plane_cfg in vkms_plane_init? This way we don't have to 
> touch vkms_output_init when adding new vkms_config_plane members.

While it'll be required once we allow to configure more parameters, I don't
think we need it right now. To keep things as simple as possible, I'd prefer to
delay it until required.

Thanks,
Jose

> > +		if (IS_ERR(plane_cfg->plane)) {
> > +			DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n");
> > +			ret = PTR_ERR(plane_cfg->plane);
> > +			goto err_free;
> > +		}
> > +
> > +		if (type == DRM_PLANE_TYPE_PRIMARY)
> > +			primary = plane_cfg->plane;
> > +		else if (type == DRM_PLANE_TYPE_CURSOR)
> > +			cursor = plane_cfg->plane;
> >  	}
> 
> [...]
Re: [PATCH 07/13] drm/vkms: Allow to configure multiple planes
Posted by Louis Chauvet 12 months ago

Le 11/02/2025 à 11:43, José Expósito a écrit :
> On Thu, Jan 30, 2025 at 02:48:19PM +0100, Louis Chauvet wrote:
>> On 29/01/25 - 12:00, José Expósito wrote:
>>> Add a list of planes to vkms_config and create as many planes as
>>> configured during output initialization.
>>>
>>> For backwards compatibility, add one primary plane and, if configured,
>>> one cursor plane and NUM_OVERLAY_PLANES planes to the default
>>> configuration.
>>>
>>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
>>> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
>>
>> Co-developped-by: Louis Chauvet <louis.chauvet@bootlin.com>
>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
>> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
>>
>> [...]
>>
>>> diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
>>
>> [...]
>>
>>> +static void vkms_config_test_get_planes(struct kunit *test)
>>> +{
>>> +	struct vkms_config *config;
>>> +	struct vkms_config_plane *plane_cfg1, *plane_cfg2;
>>> +	struct vkms_config_plane **array;
>>> +	size_t length;
>>> +
>>> +	config = vkms_config_create("test");
>>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
>>> +
>>> +	array = vkms_config_get_planes(config, &length);
>>> +	KUNIT_ASSERT_EQ(test, length, 0);
>>> +	KUNIT_ASSERT_NULL(test, array);
>>> +
>>> +	plane_cfg1 = vkms_config_add_plane(config);
>>> +	array = vkms_config_get_planes(config, &length);
>>> +	KUNIT_ASSERT_EQ(test, length, 1);
>>> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
>>> +	kfree(array);
>>> +
>>> +	plane_cfg2 = vkms_config_add_plane(config);
>>> +	array = vkms_config_get_planes(config, &length);
>>> +	KUNIT_ASSERT_EQ(test, length, 2);
>>> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg1);
>>> +	KUNIT_ASSERT_PTR_EQ(test, array[1], plane_cfg2);
>>> +	kfree(array);
>>> +
>>> +	vkms_config_destroy_plane(plane_cfg1);
>>> +	array = vkms_config_get_planes(config, &length);
>>> +	KUNIT_ASSERT_EQ(test, length, 1);
>>> +	KUNIT_ASSERT_PTR_EQ(test, array[0], plane_cfg2);
>>> +	kfree(array);
>>> +
>>> +	vkms_config_destroy(config);
>>> +}
>>
>> In this test I have the feeling that vkms_config_get_planes always returns
>> a predictable order. It is maybe trivial here, but I would prefer to shows
>> that the order is not stable, for example:
>>
>> 	bool plane_cfg1_found = false;
>> 	bool plane_cfg2_found = false;
>>
>> 	vkms_config_for_each_plane(config, plane_cfg) {
>> 		if (plane_cfg == plane_cfg1)
>> 			plane_cfg1_found = true;
>> 		else if (plane_cfg == plane_cfg2)
>> 			plane_cfg2_found = true;
>> 		else
>> 			KUNIT_FAILS("Unexpected plane");
>> 	}
>>
>> 	KUNIT_ASSERT(test, plane_cfg1_found);
>> 	KUNIT_ASSERT(test, plane_cfg2_found);
>>
>> [...]
>>
>>> +static void vkms_config_test_valid_plane_number(struct kunit *test)
>>> +{
>>> +	struct vkms_config *config;
>>> +	struct vkms_config_plane *plane_cfg;
>>> +	int n;
>>> +
>>> +	config = vkms_config_default_create(false, false, false);
>>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
>>> +
>>> +	/* Invalid: No planes */
>>> +	plane_cfg = list_first_entry(&config->planes, typeof(*plane_cfg), link);
>>> +	vkms_config_destroy_plane(plane_cfg);
>>> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
>>> +
>>> +	/* Invalid: Too many planes */
>>> +	for (n = 0; n <= 32; n++)
>>> +		vkms_config_add_plane(config);
>>> +
>>> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
>>> +
>>> +	vkms_config_destroy(config);
>>> +}
>>
>> For this function, the naming is a bit strange, it says
>> "valid_plane_number", but you test only invalid plane number.
> 
> The reason for this naming is that it tests the valid_plane_number()
> function called by vkms_config_is_valid(). The applies for the other
> valid_* tests.

Hoo, I see, okk!

> However, I don't mind changing its name to so it reflects the test
> rather than the tested function.

I prefer an "implementation independent" name, as the content of 
vkms_config_is_valid may change over time.

> Changed in v2.

Perfect!

>>
>> Can you rename it to vkms_config_test_invalid_plane_number?
>>
>> [...]
>>
>>> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
>>
>> [...]
>>
>>> +struct vkms_config_plane **vkms_config_get_planes(const struct vkms_config *config,
>>> +						  size_t *out_length)
>>> +{
>>> +	struct vkms_config_plane **array;
>>> +	struct vkms_config_plane *plane_cfg;
>>> +	size_t length;
>>> +	int n = 0;
>>> +
>>> +	length = list_count_nodes((struct list_head *)&config->planes);
>>> +	if (length == 0) {
>>> +		*out_length = length;
>>> +		return NULL;
>>> +	}
>>> +
>>> +	array = kmalloc_array(length, sizeof(*array), GFP_KERNEL);
>>> +	if (!array)
>>> +		return ERR_PTR(-ENOMEM);
>>> +
>>> +	list_for_each_entry(plane_cfg, &config->planes, link) {
>>> +		array[n] = plane_cfg;
>>> +		n++;
>>> +	}
>>> +
>>> +	*out_length = length;
>>> +	return array;
>>> +}
>>
>> To join the comment on the test, I am not a big fan of creating a new list
>> to return to the caller, for three reasons:
>> - the caller needs to manage an other pointer;
>> - the caller needs to understand that the content of the array is only
>>    valid if: the config is not freed, nobody else removed anything from the
>>    planes;
>> - the caller may think this list always have the same order if he looks at
>>    the tests.
>>
>> I would prefer a simple macro to do an iteration over the config->planes
>> list: (I did not test this macro, but you have this idea)
>>
>> 	#define vkms_config_iter_plane(config, plane_cfg) \
>> 		list_for_each_entry((plane_cfg), &(config).planes, link)
>>
>> This way:
>> - no new pointer to manage;
>> - if one day we have concurency issue, we just have to protect config, not
>>    config+all the planes;
>> - there is no expected order.
>>
>> [...]
>>
>>>   bool vkms_config_is_valid(struct vkms_config *config)
>>>   {
>>> +	if (!valid_plane_number(config))
>>> +		return false;
>>> +
>>> +	if (!valid_plane_type(config))
>>> +		return false;
>>> +
>>>   	return true;
>>>   }
>>
>> I really like the idea to split the validation function, way simpler!
>>
>> [...]
>>
>>> +void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg)
>>> +{
>>> +	list_del(&plane_cfg->link);
>>> +	kfree(plane_cfg);
>>> +}
>>
>> I would prefer a "standard" function pair, i.e.: add/remove or
>> create/destroy, not add/destroy.
>>
>> For me it should be create/destroy, you create the plane by using a
>> config, so it is clear it will be attached to it.
>>
>> If you choose add/remove, you should explains in the documentation that
>> remove is also doing kfree.
>>
>> [...]
>>
>>> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
>>
>> [...]
>>
>>> @@ -11,61 +11,63 @@ int vkms_output_init(struct vkms_device *vkmsdev)
>>>   	struct vkms_connector *connector;
>>>   	struct drm_encoder *encoder;
>>>   	struct vkms_output *output;
>>> -	struct vkms_plane *primary, *overlay, *cursor = NULL;
>>> -	int ret;
>>> +	struct vkms_plane *primary = NULL, *cursor = NULL;
>>> +	struct vkms_config_plane **plane_cfgs = NULL;
>>> +	size_t n_planes;
>>> +	int ret = 0;
>>>   	int writeback;
>>>   	unsigned int n;
>>
>> I think it could be interesting to have a vkms_config_is_valid call here.
>> It will avoid raising DRM errors or create unexpected devices.
>>
>> It will also garantee in a later patch that
>> vkms_config_crtc_get_primary_plane is a valid pointer.
>>
>>> -	/*
>>> -	 * Initialize used plane. One primary plane is required to perform the composition.
>>> -	 *
>>> -	 * The overlay and cursor planes are not mandatory, but can be used to perform complex
>>> -	 * composition.
>>> -	 */
>>> -	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
>>> -	if (IS_ERR(primary))
>>> -		return PTR_ERR(primary);
>>> +	plane_cfgs = vkms_config_get_planes(vkmsdev->config, &n_planes);
>>> +	if (IS_ERR(plane_cfgs))
>>> +		return PTR_ERR(plane_cfgs);
>>
>> If you agree on the iterator implementation, this code could be simplified
>> a lot.
>>
>>> -	if (vkmsdev->config->cursor) {
>>> -		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
>>> -		if (IS_ERR(cursor))
>>> -			return PTR_ERR(cursor);
>>> +	for (n = 0; n < n_planes; n++) {
>>> +		struct vkms_config_plane *plane_cfg;
>>> +		enum drm_plane_type type;
>>> +
>>> +		plane_cfg = plane_cfgs[n];
>>> +		type = vkms_config_plane_get_type(plane_cfg);
>>> +
>>> +		plane_cfg->plane = vkms_plane_init(vkmsdev, type);
>>
>> Can we pass plane_cfg in vkms_plane_init? This way we don't have to
>> touch vkms_output_init when adding new vkms_config_plane members.
> 
> While it'll be required once we allow to configure more parameters, I don't
> think we need it right now. To keep things as simple as possible, I'd prefer to
> delay it until required.

I understand your point, especially since your patch don't add new 
parameters to vkms_plane_init.

Thanks!

> Thanks,
> Jose
> 
>>> +		if (IS_ERR(plane_cfg->plane)) {
>>> +			DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n");
>>> +			ret = PTR_ERR(plane_cfg->plane);
>>> +			goto err_free;
>>> +		}
>>> +
>>> +		if (type == DRM_PLANE_TYPE_PRIMARY)
>>> +			primary = plane_cfg->plane;
>>> +		else if (type == DRM_PLANE_TYPE_CURSOR)
>>> +			cursor = plane_cfg->plane;
>>>   	}
>>
>> [...]

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com