1// Copyright 2016-2022 The Khronos Group Inc. 2// 3// SPDX-License-Identifier: CC-BY-4.0 4 5include::{generated}/meta/{refprefix}VK_EXT_display_control.adoc[] 6 7=== Other Extension Metadata 8 9*Last Modified Date*:: 10 2016-12-13 11*IP Status*:: 12 No known IP claims. 13*Contributors*:: 14 - Pierre Boudier, NVIDIA 15 - James Jones, NVIDIA 16 - Damien Leone, NVIDIA 17 - Pierre-Loup Griffais, Valve 18 - Daniel Vetter, Intel 19 20=== Description 21 22This extension defines a set of utility functions for use with the 23`apiext:VK_KHR_display` and `apiext:VK_KHR_display_swapchain` extensions. 24 25include::{generated}/interfaces/VK_EXT_display_control.adoc[] 26 27=== Issues 28 291) Should this extension add an explicit "`WaitForVsync`" API or a fence 30signaled at vsync that the application can wait on? 31 32*RESOLVED*: A fence. 33A separate API could later be provided that allows exporting the fence to a 34native object that could be inserted into standard run loops on POSIX and 35Windows systems. 36 372) Should callbacks be added for a vsync event, or in general to monitor 38events in Vulkan? 39 40*RESOLVED*: No, fences should be used. 41Some events are generated by interrupts which are managed in the kernel. 42In order to use a callback provided by the application, drivers would need 43to have the userspace driver spawn threads that would wait on the kernel 44event, and hence the callbacks could be difficult for the application to 45synchronize with its other work given they would arrive on a foreign thread. 46 473) Should vblank or scanline events be exposed? 48 49*RESOLVED*: Vblank events. 50Scanline events could be added by a separate extension, but the latency of 51processing an interrupt and waking up a userspace event is high enough that 52the accuracy of a scanline event would be rather low. 53Further, per-scanline interrupts are not supported by all hardware. 54 55=== Version History 56 57 * Revision 1, 2016-12-13 (James Jones) 58 ** Initial draft 59