Commit 31c0ed90 authored by Bhawanpreet Lakha's avatar Bhawanpreet Lakha Committed by Alex Deucher
Browse files

drm/amd/display: Add comments to hdcp property change code 



[Why]
These comments are helpful in understanding which case each if
statement handles.

[How]
Add comments for state transitions (9 possible cases)

Signed-off-by: default avatarBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: default avatarZhan Liu <zhan.liu@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 97f6c917

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

+24 −2
Original line number Diff line number Diff line
@@ -7238,26 +7238,35 @@ static bool is_content_protection_different(struct drm_connector_state *state, 
	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);

	struct dm_connector_state *dm_con_state = to_dm_connector_state(connector->state);



	/* Handle: Type0/1 change */

	if (old_state->hdcp_content_type != state->hdcp_content_type &&

	    state->content_protection != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {

		state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;

		return true;

	}



	/* CP is being re enabled, ignore this */

	/* CP is being re enabled, ignore this

	 *

	 * Handles:	ENABLED -> DESIRED

	 */

	if (old_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED &&

	    state->content_protection == DRM_MODE_CONTENT_PROTECTION_DESIRED) {

		state->content_protection = DRM_MODE_CONTENT_PROTECTION_ENABLED;

		return false;

	}



	/* S3 resume case, since old state will always be 0 (UNDESIRED) and the restored state will be ENABLED */

	/* S3 resume case, since old state will always be 0 (UNDESIRED) and the restored state will be ENABLED

	 *

	 * Handles:	UNDESIRED -> ENABLED

	 */

	if (old_state->content_protection == DRM_MODE_CONTENT_PROTECTION_UNDESIRED &&

	    state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED)

		state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;



	/* Check if something is connected/enabled, otherwise we start hdcp but nothing is connected/enabled

	 * hot-plug, headless s3, dpms

	 *

	 * Handles:	DESIRED -> DESIRED (Special case)

	 */

	if (dm_con_state->update_hdcp && state->content_protection == DRM_MODE_CONTENT_PROTECTION_DESIRED &&

	    connector->dpms == DRM_MODE_DPMS_ON && aconnector->dc_sink != NULL) {
@@ -7265,12 +7274,25 @@ static bool is_content_protection_different(struct drm_connector_state *state, 
		return true;

	}



	/*

	 * Handles:	UNDESIRED -> UNDESIRED

	 *		DESIRED -> DESIRED

	 *		ENABLED -> ENABLED

	 */

	if (old_state->content_protection == state->content_protection)

		return false;



	/*

	 * Handles:	UNDESIRED -> DESIRED

	 *		DESIRED -> UNDESIRED

	 *		ENABLED -> UNDESIRED

	 */

	if (state->content_protection != DRM_MODE_CONTENT_PROTECTION_ENABLED)

		return true;



	/*

	 * Handles:	DESIRED -> ENABLED

	 */

	return false;

}