drm/i915: Document ILK+ pipe csc matrix better (174d12bc) · Commits · 戴 / test

drivers/gpu/drm/i915/display/intel_color.c

+21 −5

Original line number	Diff line number	Diff line
		@@ -42,6 +42,21 @@

		#define LEGACY_LUT_LENGTH 256

		/*
		* ILK+ csc matrix:
		*
		* \|R/Cr\| \| c0 c1 c2 \| ( \|R/Cr\| \|preoff0\| ) \|postoff0\|
		* \|G/Y \| = \| c3 c4 c5 \| x ( \|G/Y \| + \|preoff1\| ) + \|postoff1\|
		* \|B/Cb\| \| c6 c7 c8 \| ( \|B/Cb\| \|preoff2\| ) \|postoff2\|
		*
		* ILK/SNB don't have explicit post offsets, and instead
		* CSC_MODE_YUV_TO_RGB and CSC_BLACK_SCREEN_OFFSET are used:
		* CSC_MODE_YUV_TO_RGB=0 + CSC_BLACK_SCREEN_OFFSET=0 -> 1/2, 0, 1/2
		* CSC_MODE_YUV_TO_RGB=0 + CSC_BLACK_SCREEN_OFFSET=1 -> 1/2, 1/16, 1/2
		* CSC_MODE_YUV_TO_RGB=1 + CSC_BLACK_SCREEN_OFFSET=0 -> 0, 0, 0
		* CSC_MODE_YUV_TO_RGB=1 + CSC_BLACK_SCREEN_OFFSET=1 -> 1/16, 1/16, 1/16
		*/

		/*
		* Extract the CSC coefficient from a CTM coefficient (in U32.32 fixed point
		* format). This macro takes the coefficient we want transformed and the
		@@ -59,37 +74,38 @@

		#define ILK_CSC_POSTOFF_LIMITED_RANGE (16 * (1 << 12) / 255)

		/* Nop pre/post offsets */
		static const u16 ilk_csc_off_zero[3] = {};

		/* Identity matrix */
		static const u16 ilk_csc_coeff_identity[9] = {
		ILK_CSC_COEFF_1_0, 0, 0,
		0, ILK_CSC_COEFF_1_0, 0,
		0, 0, ILK_CSC_COEFF_1_0,
		};

		/* Limited range RGB post offsets */
		static const u16 ilk_csc_postoff_limited_range[3] = {
		ILK_CSC_POSTOFF_LIMITED_RANGE,
		ILK_CSC_POSTOFF_LIMITED_RANGE,
		ILK_CSC_POSTOFF_LIMITED_RANGE,
		};

		/* Full range RGB -> limited range RGB matrix */
		static const u16 ilk_csc_coeff_limited_range[9] = {
		ILK_CSC_COEFF_LIMITED_RANGE, 0, 0,
		0, ILK_CSC_COEFF_LIMITED_RANGE, 0,
		0, 0, ILK_CSC_COEFF_LIMITED_RANGE,
		};

		/*
		* These values are direct register values specified in the Bspec,
		* for RGB->YUV conversion matrix (colorspace BT709)
		*/
		/* BT.709 full range RGB -> limited range YCbCr matrix */
		static const u16 ilk_csc_coeff_rgb_to_ycbcr[9] = {
		0x1e08, 0x9cc0, 0xb528,
		0x2ba8, 0x09d8, 0x37e8,
		0xbce8, 0x9ad8, 0x1e08,
		};

		/* Post offset values for RGB->YCBCR conversion */
		/* Limited range YCbCr post offsets */
		static const u16 ilk_csc_postoff_rgb_to_ycbcr[3] = {
		0x0800, 0x0100, 0x0800,
		};

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