VK_FUCHSIA_external_semaphore

Other Extension Metadata

Last Modified Date

2021-03-08

IP Status

No known IP claims.

Contributors

• Craig Stout, Google
• John Bauman, Google
• John Rosasco, Google

Description

An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from Zircon event handles.

New Commands

• vkGetSemaphoreZirconHandleFUCHSIA
• vkImportSemaphoreZirconHandleFUCHSIA

New Structures

• VkImportSemaphoreZirconHandleInfoFUCHSIA
• VkSemaphoreGetZirconHandleInfoFUCHSIA

New Enum Constants

• VK_FUCHSIA_EXTERNAL_SEMAPHORE_EXTENSION_NAME
• VK_FUCHSIA_EXTERNAL_SEMAPHORE_SPEC_VERSION
• Extending VkExternalSemaphoreHandleTypeFlagBits:
  • VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_ZIRCON_EVENT_BIT_FUCHSIA
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_ZIRCON_HANDLE_INFO_FUCHSIA
  • VK_STRUCTURE_TYPE_SEMAPHORE_GET_ZIRCON_HANDLE_INFO_FUCHSIA

Issues

1) Does the application need to close the Zircon event handle returned by vkGetSemaphoreZirconHandleFUCHSIA?

RESOLVED: Yes, unless it is passed back in to a driver instance to import the semaphore. A successful get call transfers ownership of the Zircon event handle to the application, and a successful import transfers it back to the driver. Destroying the original semaphore object will not close the Zircon event handle nor remove its reference to the underlying semaphore resource associated with it.

Version History

• Revision 1, 2021-03-08 (John Rosasco)
  • Initial revision