[PATCH] drm: document standard connector properties

[Archit Taneja]

On 11/17/2016 01:08 PM, Daniel Vetter wrote:
> There's a really big pile of additional connector properties, a lot of
> them standardized. But they're all for specific outputs (panels, TV,
> scaling, ...) so I left them out for now since this is enough for a
> start.
>
> I typed this to give Manasi a place to add her new link status
> property documentation.
>
> v2: forgot to git add all the bits (Manasi).
>
> Cc: Manasi Navare <manasi.d.navare at intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  Documentation/gpu/drm-kms.rst   |  6 ++++++
>  drivers/gpu/drm/drm_connector.c | 42 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 48 insertions(+)
>
> diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
> index 568f3c2b6e46..f19757b1736a 100644
> --- a/Documentation/gpu/drm-kms.rst
> +++ b/Documentation/gpu/drm-kms.rst
> @@ -260,6 +260,12 @@ Property Types and Blob Property Support
>  .. kernel-doc:: drivers/gpu/drm/drm_property.c
>     :export:
>
> +Standard Connector Properties
> +-----------------------------
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_connector.c
> +   :doc: standard connector properties
> +
>  Plane Composition Properties
>  ----------------------------
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index b5c6a8ee831e..385efbc6a9ef 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -588,6 +588,48 @@ static const struct drm_prop_enum_list drm_tv_subconnector_enum_list[] = {
>  DRM_ENUM_NAME_FN(drm_get_tv_subconnector_name,
>  		 drm_tv_subconnector_enum_list)
>
> +/**
> + * DOC: standard connector properties
> + *
> + * DRM connectors have a few standardized properties:
> + *
> + * EDID:
> + * 	Blob property which contains the current EDID read from the sink. This
> + * 	is useful to parse sink identification information like vendor, model
> + * 	and serial. Drivers should update this property by calling
> + * 	drm_mode_connector_update_edid_property(), usually after having parsed
> + * 	the EDID using drm_add_edid_modes(). Userspace cannot change this
> + * 	property.
> + * DPMS:
> + * 	Legacy property for setting the power state of the connector. For atomic
> + * 	drivers this is only provided for backwards compatibility with existing
> + * 	drivers, it remaps to controlling the "ACTIVE" property on the CRTC the
> + * 	connector is linked to. Drivers should never set this property directly,
> + * 	it is handled by the DRM core by calling the ->dpms() callback in
> + * 	&drm_connector_funcs. Atomic drivers should implement this hook using
> + * 	drm_atomic_helper_connector_dpms(). This is the only property standard
> + * 	connector property that userspace can change.
> + * PATH:
> + * 	Connector path property to identify how this sink is physically
> + * 	connected. Used by DP MST. This should be set by calling
> + * 	drm_mode_connector_set_path_property(), in the case of DP MST with the
> + * 	path property the MST manager created. Userspace cannot change this
> + * 	property.
> + * TILE:
> + * 	Connector tile group property to indicate how a set of DRM connector
> + * 	compose together into one logical screen. This is used by both high-res
> + * 	external screens (often only using a single cable, but exposing multiple
> + * 	DP MST sinks), or high-res integrated panels (like dual-link DSI).
> + * 	Drivers should update this property using
> + * 	drm_mode_connector_set_tile_property(). Userspace cannot change this
> + * 	property.

This contradicts the comment on @tile_blob_ptr in drm_connector.h a bit w.r.t
high-res panels.

Maybe the comment here can say "...or high-res integrated panels which aren't
genlocked"


Archit

> + *
> + * Connectors also have one standardized atomic property:
> + *
> + * CRTC_ID:
> + * 	Mode object ID of the &drm_crtc this connector should be connected to.
> + */
> +
>  int drm_connector_create_standard_properties(struct drm_device *dev)
>  {
>  	struct drm_property *prop;
>

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