Enum wayland_protocols::wp::linux_dmabuf::zv1::server::zwp_linux_buffer_params_v1::Request

#[non_exhaustive]
pub enum Request {
    Destroy,
    Add {
        fd: OwnedFd,
        plane_idx: u32,
        offset: u32,
        stride: u32,
        modifier_hi: u32,
        modifier_lo: u32,
    },
    Create {
        width: i32,
        height: i32,
        format: u32,
        flags: WEnum<Flags>,
    },
    CreateImmed {
        buffer_id: New<WlBuffer>,
        width: i32,
        height: i32,
        format: u32,
        flags: WEnum<Flags>,
    },
}

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Destroy

delete this object, used or not

Cleans up the temporary data sent to the server for dmabuf-based wl_buffer creation.

This is a destructor, once received this object cannot be used any longer.

Add

add a dmabuf to the temporary set

This request adds one dmabuf to the set in this zwp_linux_buffer_params_v1.

The 64-bit unsigned value combined from modifier_hi and modifier_lo is the dmabuf layout modifier. DRM AddFB2 ioctl calls this the fb modifier, which is defined in drm_mode.h of Linux UAPI. This is an opaque token. Drivers use this token to express tiling, compression, etc. driver-specific modifications to the base format defined by the DRM fourcc code.

Starting from version 4, the invalid_format protocol error is sent if the format + modifier pair was not advertised as supported.

Starting from version 5, the invalid_format protocol error is sent if all planes don’t use the same modifier.

This request raises the PLANE_IDX error if plane_idx is too large. The error PLANE_SET is raised if attempting to set a plane that was already set.

Fields

fd: OwnedFd

dmabuf fd

plane_idx: u32

plane index

offset: u32

offset in bytes

stride: u32

stride in bytes

modifier_hi: u32

high 32 bits of layout modifier

modifier_lo: u32

low 32 bits of layout modifier

Create

create a wl_buffer from the given dmabufs

This asks for creation of a wl_buffer from the added dmabuf buffers. The wl_buffer is not created immediately but returned via the ‘created’ event if the dmabuf sharing succeeds. The sharing may fail at runtime for reasons a client cannot predict, in which case the ‘failed’ event is triggered.

The ‘format’ argument is a DRM_FORMAT code, as defined by the libdrm’s drm_fourcc.h. The Linux kernel’s DRM sub-system is the authoritative source on how the format codes should work.

The ‘flags’ is a bitfield of the flags defined in enum “flags”. ‘y_invert’ means the that the image needs to be y-flipped.

Flag ‘interlaced’ means that the frame in the buffer is not progressive as usual, but interlaced. An interlaced buffer as supported here must always contain both top and bottom fields. The top field always begins on the first pixel row. The temporal ordering between the two fields is top field first, unless ‘bottom_first’ is specified. It is undefined whether ‘bottom_first’ is ignored if ‘interlaced’ is not set.

This protocol does not convey any information about field rate, duration, or timing, other than the relative ordering between the two fields in one buffer. A compositor may have to estimate the intended field rate from the incoming buffer rate. It is undefined whether the time of receiving wl_surface.commit with a new buffer attached, applying the wl_surface state, wl_surface.frame callback trigger, presentation, or any other point in the compositor cycle is used to measure the frame or field times. There is no support for detecting missed or late frames/fields/buffers either, and there is no support whatsoever for cooperating with interlaced compositor output.

The composited image quality resulting from the use of interlaced buffers is explicitly undefined. A compositor may use elaborate hardware features or software to deinterlace and create progressive output frames from a sequence of interlaced input buffers, or it may produce substandard image quality. However, compositors that cannot guarantee reasonable image quality in all cases are recommended to just reject all interlaced buffers.

Any argument errors, including non-positive width or height, mismatch between the number of planes and the format, bad format, bad offset or stride, may be indicated by fatal protocol errors: INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS, OUT_OF_BOUNDS.

Dmabuf import errors in the server that are not obvious client bugs are returned via the ‘failed’ event as non-fatal. This allows attempting dmabuf sharing and falling back in the client if it fails.

This request can be sent only once in the object’s lifetime, after which the only legal request is destroy. This object should be destroyed after issuing a ‘create’ request. Attempting to use this object after issuing ‘create’ raises ALREADY_USED protocol error.

It is not mandatory to issue ‘create’. If a client wants to cancel the buffer creation, it can just destroy this object.

Fields

width: i32

base plane width in pixels

height: i32

base plane height in pixels

format: u32

DRM_FORMAT code

flags: WEnum<Flags>

see enum flags

CreateImmed

immediately create a wl_buffer from the given dmabufs

This asks for immediate creation of a wl_buffer by importing the added dmabufs.

In case of import success, no event is sent from the server, and the wl_buffer is ready to be used by the client.

Upon import failure, either of the following may happen, as seen fit by the implementation:

• the client is terminated with one of the following fatal protocol errors:
• INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS, OUT_OF_BOUNDS, in case of argument errors such as mismatch between the number of planes and the format, bad format, non-positive width or height, or bad offset or stride.
• INVALID_WL_BUFFER, in case the cause for failure is unknown or platform specific.
• the server creates an invalid wl_buffer, marks it as failed and sends a ‘failed’ event to the client. The result of using this invalid wl_buffer as an argument in any request by the client is defined by the compositor implementation.

This takes the same arguments as a ‘create’ request, and obeys the same restrictions.

Only available since version 2 of the interface

Fields

buffer_id: New<WlBuffer>

id for the newly created wl_buffer

width: i32

base plane width in pixels

height: i32

base plane height in pixels

format: u32

DRM_FORMAT code

flags: WEnum<Flags>

see enum flags

Implementations

impl Request

pub fn opcode(&self) -> u16

Get the opcode number of this message

Trait Implementations

impl Debug for Request

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.