This is an proposal and a draft implementation to enable 3D LUT on drm_plane. This proposal defines a new interface for userspace applications to query hardware capabilities and to pass/enable 3D LUT functions via this DRM/KMS APIs. Overviews: ┌─────────┐ ┌─────────┐ ┌───┐ ┌──────────┐ ┌────────┐ │Userspace│◄──►│3DLUT API│◄──►│DRM│◄──►│GPU driver├──►│hardware│ └─────────┘ └─────────┘ └───┘ └──────────┘ └────────┘ 1. Userspace queries the 3DLUT mode (defined by drm_mode_3dlut_mode) from the GPU drivers (ex. amdgpu). 2. The GPU Driver replies sizes and the color depth of the 3DLUT modes, such as defined by struct lut_3d_mode_17_12bit. 3. If applicable, userspace selects and sets one of preferred 3DLUT modes by "lut_3d_mode" to driver. 4. Userspace passes 3D LUT via drm_property_blob "lut_3d". In the case of the mode "lut_3d_mode_17_12bit", the 3D LUT should have a cube size = 17x17x17 (lut_size), color depth = 12 bits (bit_depth), and X/Y/Z axis = R/G/B (color_format). 5. The GPU driver parses 3D LUT and passes it to hardware pipeline, and enables 3D LUT accordingly. Notes: 1. The patchset is based on the previous work on https://gitlab.freedesktop.org/hwentland/linux/-/tree/color-and-hdr 2. This interface can be part of the newly proposed DRM/KMS color pipeline API (https://gitlab.freedesktop.org/pq/color-and-hdr/-/issues/11). A future integration to the new API may be required or preferred, such as the followings: struct drm_color_pipeline_element { drm_color_pipeline_element_type; drm_color_pipeline_element_lut3d }; struct drm_mode_3dlut_mode -> struct drm_color_pipeline_lut3d_config struct drm_color_pipeline_lut3d { lut_3d_mode_17_12bit; }; struct drm_color_pipeline_lut3d_data { *lut_3d; }; and etc. 3. A patchset "IGT tests for pre-blending 3D LUT interfaces" for this proposal is sent to IGT mailing list. Related Work: - Enable 3D LUT to AMD display drivers (https://www.spinics.net/lists/amd-gfx/msg83032.html) Alex Hung (5): drm: Add 3D LUT mode and its attributes drm: Add Plane 3DLUT and 3DLUT mode properties drm/amd/display: Define 3D LUT struct for HDR planes drm/amd/display: Enable plane 3DLUT mode drm/amd/display: Fill 3D LUT from userspace .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 20 ++ .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 1 + .../amd/display/amdgpu_dm/amdgpu_dm_color.c | 181 ++++++++++++++++++ .../amd/display/modules/color/color_gamma.h | 12 ++ drivers/gpu/drm/drm_atomic_state_helper.c | 3 + drivers/gpu/drm/drm_atomic_uapi.c | 11 ++ drivers/gpu/drm/drm_color_mgmt.c | 68 +++++++ include/drm/drm_mode_object.h | 2 +- include/drm/drm_plane.h | 33 ++++ include/uapi/drm/drm_mode.h | 17 ++ 10 files changed, 347 insertions(+), 1 deletion(-) -- 2.37.3
