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Diffstat (limited to 'Documentation/gpu/drm-kms.rst')
| -rw-r--r-- | Documentation/gpu/drm-kms.rst | 47 |
1 files changed, 3 insertions, 44 deletions
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index 33181be97151..b1029e292e5c 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -113,6 +113,9 @@ a hardware-specific ioctl to allocate suitable buffer objects. Plane Abstraction ================= +.. kernel-doc:: drivers/gpu/drm/drm_plane.c + :doc: overview + Plane Functions Reference ------------------------- @@ -189,50 +192,6 @@ allocated and zeroed by the driver, possibly as part of a larger structure, and registered with a call to :c:func:`drm_crtc_init()` with a pointer to CRTC functions. -Planes (:c:type:`struct drm_plane <drm_plane>`) ------------------------------------------------ - -A plane represents an image source that can be blended with or overlayed -on top of a CRTC during the scanout process. Planes are associated with -a frame buffer to crop a portion of the image memory (source) and -optionally scale it to a destination size. The result is then blended -with or overlayed on top of a CRTC. - -The DRM core recognizes three types of planes: - -- DRM_PLANE_TYPE_PRIMARY represents a "main" plane for a CRTC. - Primary planes are the planes operated upon by CRTC modesetting and - flipping operations described in the page_flip hook in - :c:type:`struct drm_crtc_funcs <drm_crtc_funcs>`. -- DRM_PLANE_TYPE_CURSOR represents 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_OVERLAY represents all non-primary, non-cursor - planes. Some drivers refer to these types of planes as "sprites" - internally. - -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. - -Plane Initialization -~~~~~~~~~~~~~~~~~~~~ - -To create a plane, a KMS drivers allocates and zeroes an instances of -:c:type:`struct drm_plane <drm_plane>` (possibly as part of a -larger structure) and registers it with a call to -:c:func:`drm_universal_plane_init()`. The function takes a -bitmask of the CRTCs that can be associated with the plane, a pointer to -the plane functions, a list of format supported formats, and the type of -plane (primary, cursor, or overlay) being initialized. - -Cursor and overlay planes are optional. All drivers should provide one -primary plane per CRTC (although this requirement may change in the -future); drivers that do not wish to provide special handling for -primary planes may make use of the helper functions described in ? to -create and register a primary plane with standard capabilities. Cleanup ------- |