[PATCH] drm/connector: Add doc for content_protection tri-state

[Sean Paul]

On Fri, May 17, 2019 at 10:12 AM Harry Wentland <harry.wentland at amd.com> wrote:
>
> It was there all along in the patch description when this change was
> introduced but it would be helpful to have the same documented in the
> code.
>
> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> Cc: Sean Paul <seanpaul at chromium.org>
> Cc: Sean Paul <sean at poorly.run>
> Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>

Reviewed-by: Sean Paul <sean at poorly.run>

> ---
>  drivers/gpu/drm/drm_connector.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index b34c3d38bf15..c53e51ad3b59 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -1519,6 +1519,15 @@ EXPORT_SYMBOL(drm_connector_attach_scaling_mode_property);
>   * Content Protection is intentionally vague to allow for different underlying
>   * technologies, however it is most implemented by HDCP.
>   *
> + * The property is a tri-state with the following values:
> + * - OFF: Self explanatory, no content protection
> + * - DESIRED: Userspace requests that the driver enable protection
> + * - ENABLED: Once the driver has authenticated the link, it sets this value
> + *
> + * The driver is responsible for downgrading ENABLED to DESIRED if the link becomes
> + * unprotected. The driver should also maintain the desiredness of protection
> + * across hotplug/dpms/suspend.
> + *
>   * The content protection will be set to &drm_connector_state.content_protection
>   *
>   * Returns:
> --
> 2.21.0
>