[PATCH v2 1/3] drm: Add variable refresh rate properties to connector

[Ville Syrjälä]

On Mon, Sep 24, 2018 at 02:15:35PM -0400, Nicholas Kazlauskas wrote:
> Modern display hardware is capable of supporting variable refresh rates
> and adaptive sync technologies. The properties for querying and
> controlling these features should be exposed on the DRM connector.
> 
> This patch introduces two new properties for variable refresh rate
> support:
> 
> - variable_refresh_capable
> - variable_refresh_enabled
> 
> These are optional properties that can be added to a DRM connector
> dynamically by using drm_connector_attach_variable_refresh_properties.
> 
> DRM drivers should set variable_refresh_capable as applicable for
> their hardware. The property variable_refresh_enabled is a userspace
> controlled option.
> 
> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> ---
>  drivers/gpu/drm/drm_atomic_uapi.c |  6 ++++++
>  drivers/gpu/drm/drm_connector.c   | 35 +++++++++++++++++++++++++++++++
>  include/drm/drm_connector.h       | 27 ++++++++++++++++++++++++
>  3 files changed, 68 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> index d5b7f315098c..0bb27a24a55c 100644
> --- a/drivers/gpu/drm/drm_atomic_uapi.c
> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> @@ -723,6 +723,8 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
>  		state->content_type = val;
>  	} else if (property == connector->scaling_mode_property) {
>  		state->scaling_mode = val;
> +	} else if (property == connector->variable_refresh_enabled_property) {
> +		state->variable_refresh_enabled = val;
>  	} else if (property == connector->content_protection_property) {
>  		if (val == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
>  			DRM_DEBUG_KMS("only drivers can set CP Enabled\n");
> @@ -797,6 +799,10 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
>  		*val = state->content_type;
>  	} else if (property == connector->scaling_mode_property) {
>  		*val = state->scaling_mode;
> +	} else if (property == connector->variable_refresh_capable_property) {
> +		*val = state->variable_refresh_capable;

Immutable props don't take this path. See
__drm_object_property_get_value().

> +	} else if (property == connector->variable_refresh_enabled_property) {
> +		*val = state->variable_refresh_enabled;
>  	} else if (property == connector->content_protection_property) {
>  		*val = state->content_protection;
>  	} else if (property == config->writeback_fb_id_property) {
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 1e40e5decbe9..fc1732639bd3 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -1254,6 +1254,41 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev)
>  }
>  EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
>  
> +/**
> + * drm_connector_attach_variable_refresh_properties - creates and attaches
> + * properties for connectors that support adaptive refresh
> + * @connector: connector to create adaptive refresh properties on
> + */
> +int drm_connector_attach_variable_refresh_properties(
> +	struct drm_connector *connector)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct drm_property *prop;
> +
> +	if (!connector->variable_refresh_capable_property) {
> +		prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE,
> +			"variable_refresh_capable");
> +		if (!prop)
> +			return -ENOMEM;
> +
> +		connector->variable_refresh_capable_property = prop;
> +		drm_object_attach_property(&connector->base, prop, 0);
> +	}
> +
> +	if (!connector->variable_refresh_enabled_property) {
> +		prop = drm_property_create_bool(dev, 0,
> +			"variable_refresh_enabled");
> +		if (!prop)
> +			return -ENOMEM;
> +
> +		connector->variable_refresh_enabled_property = prop;
> +		drm_object_attach_property(&connector->base, prop, 0);
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_connector_attach_variable_refresh_properties);
> +
>  /**
>   * drm_connector_attach_scaling_mode_property - attach atomic scaling mode property
>   * @connector: connector to attach scaling mode property on.
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 91a877fa00cb..e2c26842bd50 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -449,6 +449,18 @@ struct drm_connector_state {
>  	 */
>  	unsigned int content_protection;
>  
> +	/**
> +	 * @variable_refresh_enabled: Connector property used to check
> +	 * if variable refresh is supported on the device.
> +	 */
> +	bool variable_refresh_capable;
> +
> +	/**
> +	 * @variable_refresh_enabled: Connector property used to check
> +	 * if variable refresh is enabled.
> +	 */
> +	bool variable_refresh_enabled;
> +
>  	/**
>  	 * @writeback_job: Writeback job for writeback connectors
>  	 *
> @@ -910,6 +922,19 @@ struct drm_connector {
>  	 */
>  	struct drm_property *scaling_mode_property;
>  
> +	/**
> +	 * @variable_refresh_capable_property: Optional property for
> +	 * querying hardware support for variable refresh.
> +	 */
> +	struct drm_property *variable_refresh_capable_property;
> +
> +	/**
> +	 * @variable_refresh_enabled_property: Optional property for
> +	 * enabling or disabling support for variable refresh
> +	 * on the connector.
> +	 */
> +	struct drm_property *variable_refresh_enabled_property;
> +
>  	/**
>  	 * @content_protection_property: DRM ENUM property for content
>  	 * protection. See drm_connector_attach_content_protection_property().
> @@ -1183,6 +1208,8 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev);
>  int drm_connector_attach_content_type_property(struct drm_connector *dev);
>  int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
>  					       u32 scaling_mode_mask);
> +int drm_connector_attach_variable_refresh_properties(
> +	struct drm_connector *connector);
>  int drm_connector_attach_content_protection_property(
>  		struct drm_connector *connector);
>  int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
> -- 
> 2.19.0

-- 
Ville Syrjälä
Intel