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From: Arthur Grillo <arthurgrillo@riseup.net>
Date: Wed, 06 Mar 2024 17:03:09 -0300
Subject: [PATCH 2/7] drm/vkms: Add comments
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Message-Id: <20240306-louis-vkms-conv-v1-2-5bfe7d129fdd@riseup.net>
References: <20240306-louis-vkms-conv-v1-0-5bfe7d129fdd@riseup.net>
In-Reply-To: <20240306-louis-vkms-conv-v1-0-5bfe7d129fdd@riseup.net>
To: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>, 
 Melissa Wen <melissa.srw@gmail.com>, 
 =?utf-8?q?Ma=C3=ADra_Canal?= <mairacanal@riseup.net>, 
 Haneen Mohammed <hamohammed.sa@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, 
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, 
 David Airlie <airlied@gmail.com>, arthurgrillo@riseup.net, 
 Jonathan Corbet <corbet@lwn.net>, pekka.paalanen@haloniitty.fi, 
 Louis Chauvet <louis.chauvet@bootlin.com>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
 jeremie.dautheribes@bootlin.com, miquel.raynal@bootlin.com, 
 thomas.petazzoni@bootlin.com, seanpaul@google.com, marcheu@google.com, 
 nicolejadeyee@google.com

Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
---
 drivers/gpu/drm/vkms/vkms_formats.c | 47 +++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 44d9b9b3bdc3..55ed3f598bd7 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -577,6 +577,18 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 0,
 	};
+
+	/*
+	 * Those matrixies were generated using the colour python framework
+	 *
+	 * Below are the function calls used to generate eac matrix, go to
+	 * https://colour.readthedocs.io/en/develop/generated/colour.matrix_YCbCr.html
+	 * for more info:
+	 *
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
+	 *                                  is_legal = False,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt601_full = {
 		.matrix = {
 			{ 4294967296, 0,           6021544149 },
@@ -585,6 +597,12 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 0,
 	};
+
+	/*
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
+	 *                                  is_legal = True,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt601_limited = {
 		.matrix = {
 			{ 5020601039, 0,           6881764740 },
@@ -593,6 +611,12 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 16,
 	};
+
+	/*
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
+	 *                                  is_legal = False,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt709_full = {
 		.matrix = {
 			{ 4294967296, 0,          6763714498 },
@@ -601,6 +625,12 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 0,
 	};
+
+	/*
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
+	 *                                  is_legal = True,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt709_limited = {
 		.matrix = {
 			{ 5020601039, 0,          7729959424 },
@@ -609,6 +639,12 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 16,
 	};
+
+	/*
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
+	 *                                  is_legal = False,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt2020_full = {
 		.matrix = {
 			{ 4294967296, 0,          6333358775 },
@@ -617,6 +653,12 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 0,
 	};
+
+	/*
+	 * numpy.around(colour.matrix_YCbCr(K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
+	 *                                  is_legal = True,
+	 *                                  bits = 8) * 2**32).astype(int)
+	 */
 	static struct conversion_matrix yuv_bt2020_limited = {
 		.matrix = {
 			{ 5020601039, 0,          7238124312 },
@@ -625,6 +667,11 @@ get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
 		},
 		.y_offset = 16,
 	};
+
+	/*
+	 * The next matrices are just the previous ones, but with the first and
+	 * second columns swapped
+	 */
 	static struct conversion_matrix yvu_bt601_full = {
 		.matrix = {
 			{ 4294967296, 6021544149,  0 },

-- 
2.43.0