Module dmabuf 

DMA-BUF Protocol (zwp_linux_dmabuf_v1)

Provides zero-copy buffer sharing between GPU and compositor.

On VeridianOS, DMA-BUF handles are virtio-gpu resource IDs rather than Linux file descriptors. The protocol framework remains compatible with the Wayland zwp_linux_dmabuf_v1 specification, but the underlying buffer import mechanism uses virtio-gpu resource handles instead of dmabuf fds. This allows GPU-rendered content to be composited without copying pixel data through the CPU.

Buffer lifecycle

1. Client calls create_params() to get a params builder
2. Client calls add_plane() for each plane (most formats need 1)
3. Client calls create_buffer() to finalize and import the buffer
4. The compositor can then sample from the imported buffer directly

Modules

fourcc

Common DRM fourcc pixel format codes.

modifiers

DRM format modifiers describe GPU-specific memory tiling layouts.

Structs

DmaBufBuffer

Imported DMA-BUF buffer ready for compositor use.

DmaBufFormat

DMA-BUF format descriptor (fourcc + modifier pair).

DmaBufManager

DMA-BUF manager.

DmaBufParams

DMA-BUF parameter builder (corresponds to zwp_linux_buffer_params_v1).

DmaBufPlane

Single plane of a DMA-BUF.

Constants

MAX_PLANES

Maximum number of planes per buffer

ZWP_LINUX_BUFFER_PARAMS_V1_ADD

add(fd, plane_idx, offset, stride, modifier_hi, modifier_lo)

ZWP_LINUX_BUFFER_PARAMS_V1_CREATE

create(width, height, format, flags)

ZWP_LINUX_BUFFER_PARAMS_V1_CREATED

created(buffer: new_id)

ZWP_LINUX_BUFFER_PARAMS_V1_CREATE_IMMED

create_immed(buffer_id, width, height, format, flags) – since version 2

ZWP_LINUX_BUFFER_PARAMS_V1_DESTROY

destroy

ZWP_LINUX_BUFFER_PARAMS_V1_FAILED

failed

ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_BOTTOM_FIRST

Buffer content has bottom field first

ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_INTERLACED

Buffer content is interlaced

ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_Y_INVERT

Bottom-first (y-inverted) buffer

ZWP_LINUX_DMABUF_V1

Wayland global interface name

ZWP_LINUX_DMABUF_V1_CREATE_PARAMS

create_params(id: new_id) -> zwp_linux_buffer_params_v1

ZWP_LINUX_DMABUF_V1_DESTROY

destroy

ZWP_LINUX_DMABUF_V1_FORMAT

format(format: uint) – deprecated since version 4

ZWP_LINUX_DMABUF_V1_GET_DEFAULT_FEEDBACK

get_default_feedback(id: new_id) – since version 4

ZWP_LINUX_DMABUF_V1_GET_SURFACE_FEEDBACK

get_surface_feedback(id: new_id, surface: object) – since version 4

ZWP_LINUX_DMABUF_V1_MODIFIER

modifier(format: uint, modifier_hi: uint, modifier_lo: uint) – since version 3

ZWP_LINUX_DMABUF_V1_VERSION

Protocol version