Existing LUT precision structure is having only 16 bit precision. This is not enough for upcoming enhanced hardwares and advance usecases like HDR processing. Hence added a new structure with 32 bit precision values. Also added the code, for extracting the same from values passed from userspace.
v4: Rebase
v5: Relocated the helper function to drm_color_mgmt.c. Declared the same in a header file (Alexandru Gheorghe)
v6: Enhanced gamma lut structure to take U32.32 format as input. This is needed for HDR usecase which require higher precision.
v7: Addressed Maarten's review comments and fixed the calculation.
Signed-off-by: Uma Shankar uma.shankar@intel.com Reviewed-by: Alexandru Gheorghe alexandru-cosmin.gheorghe@arm.com --- drivers/gpu/drm/drm_color_mgmt.c | 20 ++++++++++++++++++++ include/drm/drm_color_mgmt.h | 1 + include/uapi/drm/drm_mode.h | 15 +++++++++++++++ 3 files changed, 36 insertions(+)
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c index d5d34d0..79ff874 100644 --- a/drivers/gpu/drm/drm_color_mgmt.c +++ b/drivers/gpu/drm/drm_color_mgmt.c @@ -128,6 +128,26 @@ uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision) } EXPORT_SYMBOL(drm_color_lut_extract);
+/* + * Added to accommodate enhanced LUT precision. + * Max LUT precision is 32 bits. + */ +u64 drm_color_lut_extract_ext(u64 user_input, u32 bit_precision) +{ + u64 val = user_input & 0xffffffff; + u32 max = 0xffffffff >> (32 - bit_precision); + + /* Round only if we're not using full precision. */ + if (bit_precision < 32) { + val += 1UL << (32 - bit_precision - 1); + val >>= 32 - bit_precision; + } + + return ((user_input & 0xffffffff00000000) | + clamp_val(val, 0, max)); +} +EXPORT_SYMBOL(drm_color_lut_extract_ext); + /** * drm_crtc_enable_color_mgmt - enable color management properties * @crtc: DRM CRTC diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h index d1c662d..c9d2746 100644 --- a/include/drm/drm_color_mgmt.h +++ b/include/drm/drm_color_mgmt.h @@ -30,6 +30,7 @@ struct drm_plane;
uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision); +u64 drm_color_lut_extract_ext(u64 user_input, u32 bit_precision);
void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc, uint degamma_lut_size, diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 09d7296..ca81410 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -629,6 +629,21 @@ struct drm_color_lut { __u16 reserved; };
+/* + * Creating 64 bit palette entries for better data + * precision. This will be required for HDR and + * similar color processing usecases. + */ +struct drm_color_lut_ext { + /* + * Data is U32.32 fixed point format. + */ + __u64 red; + __u64 green; + __u64 blue; + __u64 reserved; +}; + #define DRM_MODE_PAGE_FLIP_EVENT 0x01 #define DRM_MODE_PAGE_FLIP_ASYNC 0x02 #define DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE 0x4