diff options
Diffstat (limited to 'drivers/gpu/drm/drm_connector.c')
| -rw-r--r-- | drivers/gpu/drm/drm_connector.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index d49e19f3de3a..cddb97f75415 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -988,6 +988,57 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = { * is no longer protected and userspace should take appropriate action * (whatever that might be). * + * HDCP Content Type: + * This Enum property is used by the userspace to declare the content type + * of the display stream, to kernel. Here display stream stands for any + * display content that userspace intended to display through HDCP + * encryption. + * + * Content Type of a stream is decided by the owner of the stream, as + * "HDCP Type0" or "HDCP Type1". + * + * The value of the property can be one of the below: + * - "HDCP Type0": DRM_MODE_HDCP_CONTENT_TYPE0 = 0 + * - "HDCP Type1": DRM_MODE_HDCP_CONTENT_TYPE1 = 1 + * + * When kernel starts the HDCP authentication (see "Content Protection" + * for details), it uses the content type in "HDCP Content Type" + * for performing the HDCP authentication with the display sink. + * + * Please note in HDCP spec versions, a link can be authenticated with + * HDCP 2.2 for Content Type 0/Content Type 1. Where as a link can be + * authenticated with HDCP1.4 only for Content Type 0(though it is implicit + * in nature. As there is no reference for Content Type in HDCP1.4). + * + * HDCP2.2 authentication protocol itself takes the "Content Type" as a + * parameter, which is a input for the DP HDCP2.2 encryption algo. + * + * In case of Type 0 content protection request, kernel driver can choose + * either of HDCP spec versions 1.4 and 2.2. When HDCP2.2 is used for + * "HDCP Type 0", a HDCP 2.2 capable repeater in the downstream can send + * that content to a HDCP 1.4 authenticated HDCP sink (Type0 link). + * But if the content is classified as "HDCP Type 1", above mentioned + * HDCP 2.2 repeater wont send the content to the HDCP sink as it can't + * authenticate the HDCP1.4 capable sink for "HDCP Type 1". + * + * Please note userspace can be ignorant of the HDCP versions used by the + * kernel driver to achieve the "HDCP Content Type". + * + * At current scenario, classifying a content as Type 1 ensures that the + * content will be displayed only through the HDCP2.2 encrypted link. + * + * Note that the HDCP Content Type property is introduced at HDCP 2.2, and + * defaults to type 0. It is only exposed by drivers supporting HDCP 2.2 + * (hence supporting Type 0 and Type 1). Based on how next versions of + * HDCP specs are defined content Type could be used for higher versions + * too. + * + * If content type is changed when "Content Protection" is not UNDESIRED, + * then kernel will disable the HDCP and re-enable with new type in the + * same atomic commit. And when "Content Protection" is ENABLED, it means + * that link is HDCP authenticated and encrypted, for the transmission of + * the Type of stream mentioned at "HDCP Content Type". + * * HDR_OUTPUT_METADATA: * Connector property to enable userspace to send HDR Metadata to * driver. This metadata is based on the composition and blending |