[PATCH v7 10/11] drm/hdcp: update content protection property with uevent

[Pekka Paalanen]

On Tue,  7 May 2019 21:57:44 +0530
Ramalingam C <ramalingam.c at intel.com> wrote:

> drm function is defined and exported to update a connector's
> content protection property state and to generate a uevent along
> with it.
> 
> Need ACK for the uevent from userspace consumer.
> 
> v2:
>   Update only when state is different from old one.
> v3:
>   KDoc is added [Daniel]
> 
> Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_hdcp.c | 32 ++++++++++++++++++++++++++++++++
>  include/drm/drm_hdcp.h     |  2 ++
>  2 files changed, 34 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
> index 75402463466b..f29b7abda51f 100644
> --- a/drivers/gpu/drm/drm_hdcp.c
> +++ b/drivers/gpu/drm/drm_hdcp.c
> @@ -372,6 +372,10 @@ DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
>   *
>   * The content protection will be set to &drm_connector_state.content_protection
>   *
> + * When kernel triggered content protection state change like DESIRED->ENABLED
> + * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
> + * the content protection state of a connector.
> + *
>   * Returns:
>   * Zero on success, negative errno on failure.
>   */
> @@ -412,3 +416,31 @@ int drm_connector_attach_content_protection_property(
>  	return 0;
>  }
>  EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
> +
> +/**
> + * drm_hdcp_update_content_protection - Updates the content protection state
> + * of a connector
> + *
> + * @connector: drm_connector on which content protection state needs an update
> + * @val: New state of the content protection property
> + *
> + * This function can be used by display drivers, to update the kernel triggered
> + * content protection state change of a drm_connector. This function update the
> + * new state of the property into the connector's state and generate an uevent
> + * to notify the userspace.
> + */
> +void drm_hdcp_update_content_protection(struct drm_connector *connector,
> +					u64 val)
> +{

Hi,

don't you need to ensure that 'val' cannot be UNDESIRED?

> +	struct drm_device *dev = connector->dev;
> +	struct drm_connector_state *state = connector->state;
> +
> +	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> +	if (state->content_protection == val)
> +		return;
> +
> +	state->content_protection = val;
> +	drm_sysfs_connector_status_event(connector,
> +				 dev->mode_config.content_protection_property);
> +}
> +EXPORT_SYMBOL(drm_hdcp_update_content_protection);
> diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
> index 2970abdfaf12..dd864ac9ce85 100644
> --- a/include/drm/drm_hdcp.h
> +++ b/include/drm/drm_hdcp.h
> @@ -292,4 +292,6 @@ bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
>  				 u8 *ksvs, u32 ksv_count);
>  int drm_connector_attach_content_protection_property(
>  		struct drm_connector *connector, bool hdcp_content_type);
> +void drm_hdcp_update_content_protection(struct drm_connector *connector,
> +					u64 val);
>  #endif

This patch is missing all UAPI documentation.

Particularly important is the detail that the kernel will not send an
event corresponding to userspace explicitly setting "Content
Protection" to "Undesired". That is what you explained to me in the
Weston MR !48, but I don't actually see it in the code here. It would
be best to enforce that in the shared DRM code.


Thanks,
pq
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