diff options
-rw-r--r-- | Documentation/gpu/drm-kms.rst | 2 | ||||
-rw-r--r-- | include/uapi/drm/drm.h | 20 | ||||
-rw-r--r-- | include/uapi/drm/drm_mode.h | 16 |
3 files changed, 36 insertions, 2 deletions
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index a0c83fc48126..270d320407c7 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -360,6 +360,8 @@ Format Functions Reference .. kernel-doc:: drivers/gpu/drm/drm_fourcc.c :export: +.. _kms_dumb_buffer_objects: + Dumb Buffer Objects =================== diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 794c1d857677..de723566c5ae 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -1134,6 +1134,26 @@ extern "C" { #define DRM_IOCTL_MODE_PAGE_FLIP DRM_IOWR(0xB0, struct drm_mode_crtc_page_flip) #define DRM_IOCTL_MODE_DIRTYFB DRM_IOWR(0xB1, struct drm_mode_fb_dirty_cmd) +/** + * DRM_IOCTL_MODE_CREATE_DUMB - Create a new dumb buffer object. + * + * KMS dumb buffers provide a very primitive way to allocate a buffer object + * suitable for scanout and map it for software rendering. KMS dumb buffers are + * not suitable for hardware-accelerated rendering nor video decoding. KMS dumb + * buffers are not suitable to be displayed on any other device than the KMS + * device where they were allocated from. Also see + * :ref:`kms_dumb_buffer_objects`. + * + * The IOCTL argument is a struct drm_mode_create_dumb. + * + * User-space is expected to create a KMS dumb buffer via this IOCTL, then add + * it as a KMS framebuffer via &DRM_IOCTL_MODE_ADDFB and map it via + * &DRM_IOCTL_MODE_MAP_DUMB. + * + * &DRM_CAP_DUMB_BUFFER indicates whether this IOCTL is supported. + * &DRM_CAP_DUMB_PREFERRED_DEPTH and &DRM_CAP_DUMB_PREFER_SHADOW indicate + * driver preferences for dumb buffers. + */ #define DRM_IOCTL_MODE_CREATE_DUMB DRM_IOWR(0xB2, struct drm_mode_create_dumb) #define DRM_IOCTL_MODE_MAP_DUMB DRM_IOWR(0xB3, struct drm_mode_map_dumb) #define DRM_IOCTL_MODE_DESTROY_DUMB DRM_IOWR(0xB4, struct drm_mode_destroy_dumb) diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index ea1b639bcb28..128d09138ceb 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -1032,13 +1032,25 @@ struct drm_mode_crtc_page_flip_target { __u64 user_data; }; -/* create a dumb scanout buffer */ +/** + * struct drm_mode_create_dumb - Create a KMS dumb buffer for scanout. + * @height: buffer height in pixels + * @width: buffer width in pixels + * @bpp: bits per pixel + * @flags: must be zero + * @handle: buffer object handle + * @pitch: number of bytes between two consecutive lines + * @size: size of the whole buffer in bytes + * + * User-space fills @height, @width, @bpp and @flags. If the IOCTL succeeds, + * the kernel fills @handle, @pitch and @size. + */ struct drm_mode_create_dumb { __u32 height; __u32 width; __u32 bpp; __u32 flags; - /* handle, pitch, size will be returned */ + __u32 handle; __u32 pitch; __u64 size; |