As many of you know, I've been writing a Vulkan extension for DRM format modifiers, named VK_EXT_image_drm_format_modifier. The extension is very close to completion. I've submitted a branch to Khronos for review. It's receiving active review inside Khronos from some non-Mesa closed-source window-system-integration people, and Mesa people too (namely jekstrand). You should take a look at the spec if you care about modifiers and Vulkan. I try to keep up-to-date urls to everything related to this extension at <http://kiwitree.net/~chadv/vulkan/#1.0-VK_EXT_image_drm_format_modifier>. There remain only two unresolved issues from my perspective: - The exact definition of members of the array VkImageDrmFormatModifierExplicitCreateInfoEXT::pPlaneLayouts. Should the extension re-use VkSubresourceLayout as the array members? Or should it define a new struct with less fields than VkSubresourceLayout? - If an image has a modifier that requires an extra plane (such as a color-compression plane), should the extension allow such an image to be disjoint? Specifically, if a modifier requires an extra plane, should the extension allow the modifier's drmFormatModifierTilingFeatures to contain VK_FORMAT_FEATURE_DISJOINT_KHR? I've tentatively concluded "no": images with extra planes must be non-disjoint. Though we could lift this restriction in a future extension. Branches ======== I maintain a public branch of the Vulkan spec, branch 1.0-VK_EXT_image_drm_format_modifier, which is synchronized with the Khronos-internal branch of the same name. I like cgit; other people like Github; so I keep a mirror at both. cgit: http://git.kiwitree.net/cgit/~chadv/vulkan-spec/log?h=1.0-VK_EXT_image_drm_format_modifier github: https://github.com/chadversary/vulkan-spec/commits/1.0-VK_EXT_image_drm_format_modifier khronos-internal: https://gitlab.khronos.org/vulkan/vulkan/merge_requests/2555 Prebuilt Specs ============== I maintain a public build of the branch. The built headers and HTML specification are synchronized with the git branch thanks to the magic of shell scripts. vulkan.h: http://git.kiwitree.net/cgit/~chadv/vulkan-spec/tree/src/vulkan/vulkan.h?h=1.0-VK_EXT_image_drm_format_modifier spec appendix: http://kiwitree.net/~chadv/vulkan/1.0-VK_EXT_image_drm_format_modifier/html/vkspec.html#VK_EXT_image_drm_format_modifier full spec: http://kiwitree.net/~chadv/vulkan/1.0-VK_EXT_image_drm_format_modifier/html/vkspec.html Where to start reading ====================== Here's a short reading guide for people unfamiliar with the extension: - Don't start with the specification. You'll quickly get lost. - First, read the VK_EXT_external_memory_dma_buf and VK_EXT_queue_family_foreign extensions. They're small extensions. They're intended to be used with VK_EXT_image_drm_format_modifier. Despite that intent, the the three extensions are independent from the Vulkan specification's perspective. - Read the appendix chapter for VK_EXT_image_drm_format_modifier. I've written an "introduction to modifiers" section in the appendix. If you're already intimately understand modifiers, then you can briefly scan this section, skipping over the boring stuff. - Read the issue section in the appendix. - Now for the tofu. Study the new structs and functions. Find them under `#define VK_EXT_image_drm_format_modifier` in vulkan.h. Also, study the new enums values. Find them by grepping 'DRM.*EXT' in vulkan.h. - Finally, go read the specification text for the new structs, functions, and enums. How to send feedback ==================== I honestly don't know. You _could_ comment on the merge request in the Khronos-internal Gitlab. But you probably (and rightfully so) want to keep the discussion public. You could provide general feedback by replying to this thread. You could leave comments on my Github branch. I don't like Github, but I can't think of a better solution, other than... I could send my specification patches to mesa-dev. If people want that, say so. So... yeah. I don't know how you should provide feedback. Just do it, and we'll iron out any problems as they arise. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
