This patch is an early RFC to discuss the viable options and alternatives for inclusion of unsigned integer formats for the DRM API. This patch adds a new single component 16-bit and a two component 32-bit DRM fourcc’s that represent unsigned integer formats. The use case for needing UINT formats, in our case, would be to support using raw buffers for camera ISPs. For images imported with DRM fourcc + modifier combination, the GPU driver needs a way to determine the datatype of the format which currently the DRM API does not provide explicitly with a notable exception of the floating-point fourccs such as DRM_FORMAT_XRGB16161616F as an example. As the DRM fourccs do not currently define the interpretation of the data, should the information be made explicit in the DRM API similarly to how it is already done in Vulkan? The reason for introducing datatype to the DRM fourcc's is that the alternative, for any API (e.g., EGL) that lacks the format datatype information for fourcc/modifier combination for dma_buf interop would be to introduce explicit additional metadata/attributes that encode this information which then would be passed to the GPU driver but the drawback of this is that it would require extending multiple graphics APIs to support every single platform. By having the DRM API expose the datatype information for formats saves a lot of integration/verification work for all of the different graphics APIs and platforms as this information could be determined by the DRM triple alone for dma_buf interop. It would be good to gather some opinions on what others think about introducing datatypes to the DRM API. Any feedback and suggestions are highly appreciated. Dennis Tsiang (1): [RFC] drm/fourcc: Add new unsigned R16_UINT/RG1616_UINT formats include/uapi/drm/drm_fourcc.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) -- 2.36.1 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
