Re: [Intel-gfx] [PATCH v5 02/10] drm/hdcp: Avoid changing crtc state in hdcp atomic check

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Apr 11, 2022 at 08:47:31PM +0000, Sean Paul wrote:
> From: Sean Paul <seanpaul@chromium.org>
> 
> Instead of forcing a modeset in the hdcp atomic check, simply return
> true if the content protection value is changing and let the driver
> decide whether a modeset is required or not.
> 
> Acked-by: Jani Nikula <jani.nikula@intel.com>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> Link: https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-3-sean@poorly.run #v1
> Link: https://patchwork.freedesktop.org/patch/msgid/20210915203834.1439-3-sean@poorly.run #v2
> Link: https://patchwork.freedesktop.org/patch/msgid/20211001151145.55916-3-sean@poorly.run #v3
> Link: https://patchwork.freedesktop.org/patch/msgid/20211105030434.2828845-3-sean@poorly.run #v4
> 
> Changes in v2:
> -None
> Changes in v3:
> -None
> Changes in v4:
> -None
> Changes in v5:
> -None
> ---
>  drivers/gpu/drm/drm_hdcp.c                  | 33 +++++++++++++++------
>  drivers/gpu/drm/i915/display/intel_atomic.c |  5 ++--
>  include/drm/drm_hdcp.h                      |  2 +-
>  3 files changed, 27 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
> index 522326b03e66..dd8fa91c51d6 100644
> --- a/drivers/gpu/drm/drm_hdcp.c
> +++ b/drivers/gpu/drm/drm_hdcp.c
> @@ -430,11 +430,14 @@ EXPORT_SYMBOL(drm_hdcp_update_content_protection);
>   * @connector: drm_connector on which content protection state needs an update
>   *
>   * This function can be used by display drivers to perform an atomic check on the
> - * hdcp state elements. If hdcp state has changed, this function will set
> - * mode_changed on the crtc driving the connector so it can update its hardware
> - * to match the hdcp state.
> + * hdcp state elements. If hdcp state has changed in a manner which requires the
> + * driver to enable or disable content protection, this function will return
> + * true.
> + *
> + * Returns:
> + * true if the driver must enable/disable hdcp, false otherwise
>   */
> -void drm_hdcp_atomic_check(struct drm_connector *connector,
> +bool drm_hdcp_atomic_check(struct drm_connector *connector,
>  			   struct drm_atomic_state *state)
>  {
>  	struct drm_connector_state *new_conn_state, *old_conn_state;
> @@ -452,10 +455,12 @@ void drm_hdcp_atomic_check(struct drm_connector *connector,
>  		 * If the connector is being disabled with CP enabled, mark it
>  		 * desired so it's re-enabled when the connector is brought back
>  		 */
> -		if (old_hdcp == DRM_MODE_CONTENT_PROTECTION_ENABLED)
> +		if (old_hdcp == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
>  			new_conn_state->content_protection =
>  				DRM_MODE_CONTENT_PROTECTION_DESIRED;
> -		return;
> +			return true;
> +		}
> +		return false;
>  	}
>  
>  	new_crtc_state = drm_atomic_get_new_crtc_state(state,
> @@ -467,9 +472,19 @@ void drm_hdcp_atomic_check(struct drm_connector *connector,
>  	*/
>  	if (drm_atomic_crtc_needs_modeset(new_crtc_state) &&
>  	    (old_hdcp == DRM_MODE_CONTENT_PROTECTION_ENABLED &&
> -	     new_hdcp != DRM_MODE_CONTENT_PROTECTION_UNDESIRED))
> +	     new_hdcp != DRM_MODE_CONTENT_PROTECTION_UNDESIRED)) {
>  		new_conn_state->content_protection =
>  			DRM_MODE_CONTENT_PROTECTION_DESIRED;
> +		return true;
> +	}
> +
> +	/*
> +	 * Coming back from disable or changing CRTC with DESIRED state requires
> +	 * that the driver try CP enable.
> +	 */
> +	if (new_hdcp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
> +	    new_conn_state->crtc != old_conn_state->crtc)
> +		return true;

I'm with the feeling that this chunk should deserve a separated patch.
But the reason looks correct so anyway

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

>  
>  	/*
>  	 * Nothing to do if content type is unchanged and one of:
> @@ -484,9 +499,9 @@ void drm_hdcp_atomic_check(struct drm_connector *connector,
>  	     new_hdcp == DRM_MODE_CONTENT_PROTECTION_DESIRED)) {
>  		if (old_conn_state->hdcp_content_type ==
>  				new_conn_state->hdcp_content_type)
> -			return;
> +			return false;
>  	}
>  
> -	new_crtc_state->mode_changed = true;
> +	return true;
>  }
>  EXPORT_SYMBOL(drm_hdcp_atomic_check);
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> index b301a4d1017e..6d24b3450399 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> @@ -124,8 +124,6 @@ int intel_digital_connector_atomic_check(struct drm_connector *conn,
>  		to_intel_digital_connector_state(old_state);
>  	struct drm_crtc_state *crtc_state;
>  
> -	drm_hdcp_atomic_check(conn, state);
> -
>  	if (!new_state->crtc)
>  		return 0;
>  
> @@ -142,7 +140,8 @@ int intel_digital_connector_atomic_check(struct drm_connector *conn,
>  	    new_conn_state->base.content_type != old_conn_state->base.content_type ||
>  	    new_conn_state->base.scaling_mode != old_conn_state->base.scaling_mode ||
>  	    new_conn_state->base.privacy_screen_sw_state != old_conn_state->base.privacy_screen_sw_state ||
> -	    !drm_connector_atomic_hdr_metadata_equal(old_state, new_state))
> +	    !drm_connector_atomic_hdr_metadata_equal(old_state, new_state) ||
> +	    drm_hdcp_atomic_check(conn, state))
>  		crtc_state->mode_changed = true;
>  
>  	return 0;
> diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
> index d49977a042e1..e6e3d16bc7d3 100644
> --- a/include/drm/drm_hdcp.h
> +++ b/include/drm/drm_hdcp.h
> @@ -301,7 +301,7 @@ 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);
> -void drm_hdcp_atomic_check(struct drm_connector *connector,
> +bool drm_hdcp_atomic_check(struct drm_connector *connector,
>  			   struct drm_atomic_state *state);
>  
>  /* Content Type classification for HDCP2.2 vs others */
> -- 
> Sean Paul, Software Engineer, Google / Chromium OS
>