Message-ID: <Z636vcUzinD0vxa3@louis-chauvet-laptop>
Date: Thu, 13 Feb 2025 14:59:25 +0100
From: Louis Chauvet <louis.chauvet@...tlin.com>
To: José Expósito <jose.exposito89@...il.com>
Cc: hamohammed.sa@...il.com, simona@...ll.ch, melissa.srw@...il.com,
	maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
	tzimmermann@...e.de, airlied@...il.com,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 14/15] drm/vkms: Allow to configure multiple connectors

On 11/02/25 - 12:09, José Expósito wrote:
> Add a list of connectors to vkms_config and helper functions to add and
> remove as many connectors as wanted.
> 
> For backwards compatibility, add one enabled connector to the default
> configuration.
> 
> A future patch will allow to attach connectors and encoders, but for the
> moment there are no changes in the way the output is configured.
> 
> Co-developed-by: Louis Chauvet <louis.chauvet@...tlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@...tlin.com>
> Signed-off-by: José Expósito <jose.exposito89@...il.com>

Compilation as module is broken:

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index d06540ab9d15..9ba857ce1732 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -555,9 +555,11 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *c

        return connector_cfg;
 }
+EXPORT_SYMBOL_IF_KUNIT(vkms_config_create_connector);

 void vkms_config_destroy_connector(struct vkms_config_connector *connector_cfg)
 {
        list_del(&connector_cfg->link);
        kfree(connector_cfg);
 }
+EXPORT_SYMBOL_IF_KUNIT(vkms_config_destroy_connector);


> ---
>  .clang-format                                 |  1 +
>  drivers/gpu/drm/vkms/tests/vkms_config_test.c | 74 +++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_config.c            | 50 +++++++++++++
>  drivers/gpu/drm/vkms/vkms_config.h            | 42 +++++++++++
>  drivers/gpu/drm/vkms/vkms_connector.c         | 11 +++
>  5 files changed, 178 insertions(+)
> 
> diff --git a/.clang-format b/.clang-format
> index 5d21c0e4edbd..ca49832993c5 100644
> --- a/.clang-format
> +++ b/.clang-format
> @@ -690,6 +690,7 @@ ForEachMacros:
>    - 'v4l2_m2m_for_each_src_buf'
>    - 'v4l2_m2m_for_each_src_buf_safe'
>    - 'virtio_device_for_each_vq'
> +  - 'vkms_config_for_each_connector'
>    - 'vkms_config_for_each_crtc'
>    - 'vkms_config_for_each_encoder'
>    - 'vkms_config_for_each_plane'
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> index 7458d175acb6..cba7e9d2fcad 100644
> --- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> +++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> @@ -27,6 +27,7 @@ static void vkms_config_test_empty_config(struct kunit *test)
>  	KUNIT_EXPECT_TRUE(test, list_empty(&config->planes));
>  	KUNIT_EXPECT_TRUE(test, list_empty(&config->crtcs));
>  	KUNIT_EXPECT_TRUE(test, list_empty(&config->encoders));
> +	KUNIT_EXPECT_TRUE(test, list_empty(&config->connectors));
>  
>  	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
>  
> @@ -103,6 +104,9 @@ static void vkms_config_test_default_config(struct kunit *test)
>  	/* Encoders */
>  	KUNIT_EXPECT_EQ(test, list_count_nodes(&config->encoders), 1);
>  
> +	/* Connectors */
> +	KUNIT_EXPECT_EQ(test, list_count_nodes(&config->connectors), 1);
> +
>  	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
>  
>  	vkms_config_destroy(config);
> @@ -232,6 +236,51 @@ static void vkms_config_test_get_encoders(struct kunit *test)
>  	vkms_config_destroy(config);
>  }
>  
> +static void vkms_config_test_get_connectors(struct kunit *test)
> +{
> +	struct vkms_config *config;
> +	struct vkms_config_connector *connector_cfg;
> +	struct vkms_config_connector *connector_cfg1, *connector_cfg2;
> +	int n_connectors = 0;
> +
> +	config = vkms_config_create("test");
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> +
> +	vkms_config_for_each_connector(config, connector_cfg)
> +		n_connectors++;
> +	KUNIT_ASSERT_EQ(test, n_connectors, 0);
> +
> +	connector_cfg1 = vkms_config_create_connector(config);
> +	vkms_config_for_each_connector(config, connector_cfg) {
> +		n_connectors++;
> +		if (connector_cfg != connector_cfg1)
> +			KUNIT_FAIL(test, "Unexpected connector");
> +	}
> +	KUNIT_ASSERT_EQ(test, n_connectors, 1);
> +	n_connectors = 0;
> +
> +	connector_cfg2 = vkms_config_create_connector(config);
> +	vkms_config_for_each_connector(config, connector_cfg) {
> +		n_connectors++;
> +		if (connector_cfg != connector_cfg1 &&
> +		    connector_cfg != connector_cfg2)
> +			KUNIT_FAIL(test, "Unexpected connector");
> +	}
> +	KUNIT_ASSERT_EQ(test, n_connectors, 2);
> +	n_connectors = 0;
> +
> +	vkms_config_destroy_connector(connector_cfg2);
> +	vkms_config_for_each_connector(config, connector_cfg) {
> +		n_connectors++;
> +		if (connector_cfg != connector_cfg1)
> +			KUNIT_FAIL(test, "Unexpected connector");
> +	}
> +	KUNIT_ASSERT_EQ(test, n_connectors, 1);
> +	n_connectors = 0;
> +
> +	vkms_config_destroy(config);
> +}
> +
>  static void vkms_config_test_invalid_plane_number(struct kunit *test)
>  {
>  	struct vkms_config *config;
> @@ -439,6 +488,29 @@ static void vkms_config_test_valid_encoder_possible_crtcs(struct kunit *test)
>  	vkms_config_destroy(config);
>  }
>  
> +static void vkms_config_test_invalid_connector_number(struct kunit *test)
> +{
> +	struct vkms_config *config;
> +	struct vkms_config_connector *connector_cfg;
> +	int n;
> +
> +	config = vkms_config_default_create(false, false, false);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> +
> +	/* Invalid: No connectors */
> +	connector_cfg = list_first_entry(&config->connectors, typeof(*connector_cfg), link);
> +	vkms_config_destroy_connector(connector_cfg);
> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> +
> +	/* Invalid: Too many connectors */
> +	for (n = 0; n <= 32; n++)
> +		connector_cfg = vkms_config_create_connector(config);
> +
> +	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
> +
> +	vkms_config_destroy(config);
> +}
> +
>  static void vkms_config_test_plane_attach_crtc(struct kunit *test)
>  {
>  	struct vkms_config *config;
> @@ -635,12 +707,14 @@ static struct kunit_case vkms_config_test_cases[] = {
>  	KUNIT_CASE(vkms_config_test_get_planes),
>  	KUNIT_CASE(vkms_config_test_get_crtcs),
>  	KUNIT_CASE(vkms_config_test_get_encoders),
> +	KUNIT_CASE(vkms_config_test_get_connectors),
>  	KUNIT_CASE(vkms_config_test_invalid_plane_number),
>  	KUNIT_CASE(vkms_config_test_valid_plane_type),
>  	KUNIT_CASE(vkms_config_test_valid_plane_possible_crtcs),
>  	KUNIT_CASE(vkms_config_test_invalid_crtc_number),
>  	KUNIT_CASE(vkms_config_test_invalid_encoder_number),
>  	KUNIT_CASE(vkms_config_test_valid_encoder_possible_crtcs),
> +	KUNIT_CASE(vkms_config_test_invalid_connector_number),
>  	KUNIT_CASE(vkms_config_test_plane_attach_crtc),
>  	KUNIT_CASE(vkms_config_test_plane_get_possible_crtcs),
>  	KUNIT_CASE(vkms_config_test_encoder_get_possible_crtcs),
> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
> index f727c0009489..d52280d3bbee 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.c
> +++ b/drivers/gpu/drm/vkms/vkms_config.c
> @@ -24,6 +24,7 @@ struct vkms_config *vkms_config_create(const char *dev_name)
>  	INIT_LIST_HEAD(&config->planes);
>  	INIT_LIST_HEAD(&config->crtcs);
>  	INIT_LIST_HEAD(&config->encoders);
> +	INIT_LIST_HEAD(&config->connectors);
>  
>  	return config;
>  }
> @@ -36,6 +37,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
>  	struct vkms_config_plane *plane_cfg;
>  	struct vkms_config_crtc *crtc_cfg;
>  	struct vkms_config_encoder *encoder_cfg;
> +	struct vkms_config_connector *connector_cfg;
>  	int n;
>  
>  	config = vkms_config_create(DEFAULT_DEVICE_NAME);
> @@ -87,6 +89,10 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
>  	if (vkms_config_encoder_attach_crtc(encoder_cfg, crtc_cfg))
>  		goto err_alloc;
>  
> +	connector_cfg = vkms_config_create_connector(config);
> +	if (IS_ERR(connector_cfg))
> +		goto err_alloc;
> +
>  	return config;
>  
>  err_alloc:
> @@ -99,6 +105,7 @@ void vkms_config_destroy(struct vkms_config *config)
>  	struct vkms_config_plane *plane_cfg, *plane_tmp;
>  	struct vkms_config_crtc *crtc_cfg, *crtc_tmp;
>  	struct vkms_config_encoder *encoder_cfg, *encoder_tmp;
> +	struct vkms_config_connector *connector_cfg, *connector_tmp;
>  
>  	list_for_each_entry_safe(plane_cfg, plane_tmp, &config->planes, link)
>  		vkms_config_destroy_plane(plane_cfg);
> @@ -109,6 +116,9 @@ void vkms_config_destroy(struct vkms_config *config)
>  	list_for_each_entry_safe(encoder_cfg, encoder_tmp, &config->encoders, link)
>  		vkms_config_destroy_encoder(config, encoder_cfg);
>  
> +	list_for_each_entry_safe(connector_cfg, connector_tmp, &config->connectors, link)
> +		vkms_config_destroy_connector(connector_cfg);
> +
>  	kfree_const(config->dev_name);
>  	kfree(config);
>  }
> @@ -251,6 +261,20 @@ static bool valid_encoder_possible_crtcs(struct vkms_config *config)
>  	return true;
>  }
>  
> +static bool valid_connector_number(struct vkms_config *config)
> +{
> +	struct drm_device *dev = &config->dev->drm;
> +	size_t n_connectors;
> +
> +	n_connectors = list_count_nodes(&config->connectors);
> +	if (n_connectors <= 0 || n_connectors >= 32) {
> +		drm_info(dev, "The number of connectors must be between 1 and 31\n");
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>  bool vkms_config_is_valid(struct vkms_config *config)
>  {
>  	struct vkms_config_crtc *crtc_cfg;
> @@ -264,6 +288,9 @@ bool vkms_config_is_valid(struct vkms_config *config)
>  	if (!valid_encoder_number(config))
>  		return false;
>  
> +	if (!valid_connector_number(config))
> +		return false;
> +
>  	if (!valid_plane_possible_crtcs(config))
>  		return false;
>  
> @@ -287,6 +314,7 @@ static int vkms_config_show(struct seq_file *m, void *data)
>  	struct vkms_config_plane *plane_cfg;
>  	struct vkms_config_crtc *crtc_cfg;
>  	struct vkms_config_encoder *encoder_cfg;
> +	struct vkms_config_connector *connector_cfg;
>  
>  	dev_name = vkms_config_get_device_name((struct vkms_config *)vkmsdev->config);
>  	seq_printf(m, "dev_name=%s\n", dev_name);
> @@ -306,6 +334,9 @@ static int vkms_config_show(struct seq_file *m, void *data)
>  	vkms_config_for_each_encoder(vkmsdev->config, encoder_cfg)
>  		seq_puts(m, "encoder\n");
>  
> +	vkms_config_for_each_connector(vkmsdev->config, connector_cfg)
> +		seq_puts(m, "connector\n");
> +
>  	return 0;
>  }
>  
> @@ -494,3 +525,22 @@ void vkms_config_encoder_detach_crtc(struct vkms_config_encoder *encoder_cfg,
>  			xa_erase(&encoder_cfg->possible_crtcs, idx);
>  	}
>  }
> +
> +struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *config)
> +{
> +	struct vkms_config_connector *connector_cfg;
> +
> +	connector_cfg = kzalloc(sizeof(*connector_cfg), GFP_KERNEL);
> +	if (!connector_cfg)
> +		return ERR_PTR(-ENOMEM);
> +
> +	list_add_tail(&connector_cfg->link, &config->connectors);
> +
> +	return connector_cfg;
> +}
> +
> +void vkms_config_destroy_connector(struct vkms_config_connector *connector_cfg)
> +{
> +	list_del(&connector_cfg->link);
> +	kfree(connector_cfg);
> +}
> diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
> index 28c24afebe1e..8451c2f127b6 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.h
> +++ b/drivers/gpu/drm/vkms/vkms_config.h
> @@ -16,6 +16,7 @@
>   * @planes: List of planes configured for the device
>   * @crtcs: List of CRTCs configured for the device
>   * @encoders: List of encoders configured for the device
> + * @connectors: List of connectors configured for the device
>   * @dev: Used to store the current VKMS device. Only set when the device is instantiated.
>   */
>  struct vkms_config {
> @@ -23,6 +24,7 @@ struct vkms_config {
>  	struct list_head planes;
>  	struct list_head crtcs;
>  	struct list_head encoders;
> +	struct list_head connectors;
>  	struct vkms_device *dev;
>  };
>  
> @@ -86,6 +88,22 @@ struct vkms_config_encoder {
>  	struct drm_encoder *encoder;
>  };
>  
> +/**
> + * struct vkms_config_connector
> + *
> + * @link: Link to the others connector in vkms_config
> + * @connector: Internal usage. This pointer should never be considered as valid.
> + *             It can be used to store a temporary reference to a VKMS connector
> + *             during device creation. This pointer is not managed by the
> + *             configuration and must be managed by other means.
> + */
> +struct vkms_config_connector {
> +	struct list_head link;
> +
> +	/* Internal usage */
> +	struct vkms_connector *connector;
> +};
> +
>  /**
>   * vkms_config_for_each_plane - Iterate over the vkms_config planes
>   * @config: &struct vkms_config pointer
> @@ -110,6 +128,14 @@ struct vkms_config_encoder {
>  #define vkms_config_for_each_encoder(config, encoder_cfg) \
>  	list_for_each_entry((encoder_cfg), &(config)->encoders, link)
>  
> +/**
> + * vkms_config_for_each_connector - Iterate over the vkms_config connectors
> + * @config: &struct vkms_config pointer
> + * @connector_cfg: &struct vkms_config_connector pointer used as cursor
> + */
> +#define vkms_config_for_each_connector(config, connector_cfg) \
> +	list_for_each_entry((connector_cfg), &(config)->connectors, link)
> +
>  /**
>   * vkms_config_plane_for_each_possible_crtc - Iterate over the vkms_config_plane
>   * possible CRTCs
> @@ -355,4 +381,20 @@ int __must_check vkms_config_encoder_attach_crtc(struct vkms_config_encoder *enc
>  void vkms_config_encoder_detach_crtc(struct vkms_config_encoder *encoder_cfg,
>  				     struct vkms_config_crtc *crtc_cfg);
>  
> +/**
> + * vkms_config_create_connector() - Add a new connector configuration
> + * @config: Configuration to add the connector to
> + *
> + * Returns:
> + * The new connector configuration or an error. Call
> + * vkms_config_destroy_connector() to free the returned connector configuration.
> + */
> +struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *config);
> +
> +/**
> + * vkms_config_destroy_connector() - Remove and free a connector configuration
> + * @connector_cfg: Connector configuration to destroy
> + */
> +void vkms_config_destroy_connector(struct vkms_config_connector *connector_cfg);
> +
>  #endif /* _VKMS_CONFIG_H_ */
> diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
> index ab8b52a84151..48b10cba322a 100644
> --- a/drivers/gpu/drm/vkms/vkms_connector.c
> +++ b/drivers/gpu/drm/vkms/vkms_connector.c
> @@ -25,8 +25,19 @@ static int vkms_conn_get_modes(struct drm_connector *connector)
>  	return count;
>  }
>  
> +static struct drm_encoder *vkms_conn_best_encoder(struct drm_connector *connector)
> +{
> +	struct drm_encoder *encoder;
> +
> +	drm_connector_for_each_possible_encoder(connector, encoder)
> +		return encoder;
> +
> +	return NULL;
> +}
> +
>  static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
>  	.get_modes    = vkms_conn_get_modes,
> +	.best_encoder = vkms_conn_best_encoder,
>  };
>  
>  struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev)
> -- 
> 2.48.1
> 

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