Re: [PATCH 05/10] drm/doc: Polish for drm_plane.[hc]

[Archit Taneja <architt@codeaurora.org>]

On 8/31/2016 9:39 PM, Daniel Vetter wrote:
> Big thing is untangling and carefully documenting the different uapi
> types of planes. I also sprinkled a few more cross references around
> to make this easier to discover.
>
> As usual, remove the kerneldoc for internal functions which are not
> exported. Aside: We should probably go OCD on all the ioctl handlers
> and consistenly give them an _ioctl postfix.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>   Documentation/gpu/drm-kms.rst |  47 +--------------
>   drivers/gpu/drm/drm_crtc.c    |   6 +-
>   drivers/gpu/drm/drm_plane.c   | 132 ++++++++----------------------------------
>   include/drm/drm_plane.h       |  57 +++++++++++++++++-
>   4 files changed, 86 insertions(+), 156 deletions(-)
>
<snip>

> +/**
> + * enum drm_plane_type - uapi plane type enumeration
> + *
> + * For historical reasons not all planes are made the same. This enumeration is
> + * used to tell the different types of planes apart to implement the different
> + * uapi semantics for them. For userspace which is universal plane aware and
> + * which is using that atomic IOCTL there's no difference between these planes
> + * (beyong what the driver and hardware can support of course).
> + *
> + * For compatibility with legacy userspace, only overlay planes are made
> + * available to userspace by default. Userspace clients may set the
> + * DRM_CLIENT_CAP_UNIVERSAL_PLANES client capability bit to indicate that they
> + * wish to receive a universal plane list containing all plane types. See also
> + * drm_for_each_legacy_plane().
> + */
>   enum drm_plane_type {
> -	DRM_PLANE_TYPE_OVERLAY,

Any reason why you moved this down? I guess there is no harm, but people
might be printing plane type while debugging, and they'd assume
DRM_PLANE_TYPE_OVERLAY=0

Thanks,
Archit

> +	/**
> +	 * @DRM_PLANE_TYPE_PRIMARY:
> +	 *
> +	 * Primary planes represent a "main" plane for a CRTC.  Primary planes
> +	 * are the planes operated upon by CRTC modesetting and flipping
> +	 * operations described in the page_flip and set_config hooks in struct
> +	 * &drm_crtc_funcs.
> +	 */
>   	DRM_PLANE_TYPE_PRIMARY,
> +
> +	/**
> +	 * @DRM_PLANE_TYPE_CURSOR:
> +	 *
> +	 * Cursor planes represent a "cursor" plane for a CRTC.  Cursor planes
> +	 * are the planes operated upon by the DRM_IOCTL_MODE_CURSOR and
> +	 * DRM_IOCTL_MODE_CURSOR2 IOCTLs.
> +	 */
>   	DRM_PLANE_TYPE_CURSOR,
> +
> +	/**
> +	 * @DRM_PLANE_TYPE_OVERLAY:
> +	 *
> +	 * Overlay planes represent all non-primary, non-cursor planes. Some
> +	 * drivers refer to these types of planes as "sprites" internally.
> +	 */
> +	DRM_PLANE_TYPE_OVERLAY,
>   };
>
>
> @@ -458,11 +496,26 @@ static inline struct drm_plane *drm_plane_find(struct drm_device *dev,
>   	list_for_each_entry((plane), &(dev)->mode_config.plane_list, head) \
>   		for_each_if ((plane_mask) & (1 << drm_plane_index(plane)))
>
> -/* Plane list iterator for legacy (overlay only) planes. */
> +/**
> + * drm_for_each_legacy_plane - iterate over all planes for legacy userspace
> + * @plane: the loop cursor
> + * @dev: the DRM device
> + *
> + * Iterate over all legacy planes of @dev, excluding primary and cursor planes.
> + * This is useful for implementing userspace apis when userspace is not
> + * universal plane aware. See also enum &drm_plane_type.
> + */
>   #define drm_for_each_legacy_plane(plane, dev) \
>   	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head) \
>   		for_each_if (plane->type == DRM_PLANE_TYPE_OVERLAY)
>
> +/**
> + * drm_for_each_plane - iterate over all planes
> + * @plane: the loop cursor
> + * @dev: the DRM device
> + *
> + * Iterate over all planes of @dev, include primary and cursor planes.
> + */
>   #define drm_for_each_plane(plane, dev) \
>   	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head)
>
>

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