// Copyright 2016-2023 The Khronos Group Inc.
//
// SPDX-License-Identifier: CC-BY-4.0

include::{generated}/meta/{refprefix}VK_KHR_maintenance4.adoc[]

=== Other Extension Metadata

*Last Modified Date*::
    2021-10-25
*Interactions and External Dependencies*::
  - Promoted to Vulkan 1.3 Core
  - Requires SPIR-V 1.2 for code:LocalSizeId
*Contributors*::
  - Lionel Duc, NVIDIA
  - Faith Ekstrand, Intel
  - Spencer Fricke, Samsung
  - Tobias Hector, AMD
  - Lionel Landwerlin, Intel
  - Graeme Leese, Broadcom
  - Tom Olson, Arm
  - Stu Smith, AMD
  - Yiwei Zhang, Google

=== Description

`VK_KHR_maintenance4` adds a collection of minor features, none of which
would warrant an entire extension of their own.

The new features are as follows:

  * Allow the application to destroy their slink:VkPipelineLayout object
    immediately after it was used to create another object.
    It is no longer necessary to keep its handle valid while the created
    object is in use.
  * Add a new <<limits-maxBufferSize, pname:maxBufferSize>>
    implementation-defined limit for the maximum size sname:VkBuffer that
    can: be created.
  * Add support for the SPIR-V 1.2 code:LocalSizeId execution mode, which
    can be used as an alternative to code:LocalSize to specify the local
    workgroup size with specialization constants.
  * Add a guarantee that images created with identical creation parameters
    will always have the same alignment requirements.
  * Add new flink:vkGetDeviceBufferMemoryRequirementsKHR,
    flink:vkGetDeviceImageMemoryRequirementsKHR, and
    flink:vkGetDeviceImageSparseMemoryRequirementsKHR to allow the
    application to query the image memory requirements without having to
    create an image object and query it.
  * Relax the requirement that push constants must be initialized before
    they are dynamically accessed.
  * Relax the interface matching rules to allow a larger output vector to
    match with a smaller input vector, with additional values being
    discarded.
  * Add a guarantee for buffer memory requirement that the size memory
    requirement is never greater than the result of aligning create size
    with the alignment memory requirement.

include::{generated}/interfaces/VK_KHR_maintenance4.adoc[]

=== Promotion to Vulkan 1.3

Functionality in this extension is included in core Vulkan 1.3, with the KHR
suffix omitted.
The original type, enum and command names are still available as aliases of
the core functionality.

=== Issues

None.

=== Version History

  * Revision 1, 2021-08-18 (Piers Daniell)
  ** Internal revisions
  * Revision 2, 2021-10-25 (Yiwei Zhang)
  ** More guarantees on buffer memory requirements