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.
Signed-off-by: Uma Shankar <uma.shan...@intel.com>
---
drivers/gpu/drm/drm_plane.c | 19 +++++++++++++++++++
include/uapi/drm/drm_mode.h | 15 +++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index a5d1fc7..e706da6 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -426,6 +426,25 @@ void drm_plane_force_disable(struct drm_plane *plane)
}
EXPORT_SYMBOL(drm_plane_force_disable);
+/*
+ * Added to accommodate enhanced LUT precision.
+ * Max LUT precision is 32 bits.
+ */
+uint32_t drm_color_lut_extract_ext(uint32_t user_input, uint32_t bit_precision)
+{
+ uint32_t val = user_input;
+ uint32_t 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 clamp_val(val, 0, max);
+}
+EXPORT_SYMBOL(drm_color_lut_extract_ext);
+
/**
* drm_mode_plane_set_obj_prop - set the value of a property
* @plane: drm plane object to set property value for
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index b5d7d9e..5f3ed88 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -615,6 +615,21 @@ struct drm_color_lut {
__u16 reserved;
};
+/*
+ * Creating 32 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 U0.32 fixed point format.
+ */
+ __u32 red;
+ __u32 green;
+ __u32 blue;
+ __u32 reserved;
+};
+
#define DRM_MODE_PAGE_FLIP_EVENT 0x01
#define DRM_MODE_PAGE_FLIP_ASYNC 0x02
#define DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE 0x4
--
1.9.1
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