From: Melissa Wen <mwen@igalia.com>
To: amd-gfx@lists.freedesktop.org,
Harry Wentland <harry.wentland@amd.com>,
Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
sunpeng.li@amd.com, Alex Deucher <alexander.deucher@amd.com>,
dri-devel@lists.freedesktop.org, christian.koenig@amd.com,
Xinhui.Pan@amd.com, airlied@gmail.com, daniel@ffwll.ch
Cc: Sebastian Wick <sebastian.wick@redhat.com>,
Pekka Paalanen <pekka.paalanen@collabora.com>,
Shashank Sharma <Shashank.Sharma@amd.com>,
Alex Hung <alex.hung@amd.com>, Simon Ser <contact@emersion.fr>,
Xaver Hugl <xaver.hugl@gmail.com>,
kernel-dev@igalia.com,
Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>,
Joshua Ashton <joshua@froggi.es>,
sungjoon.kim@amd.com
Subject: [PATCH v3 07/32] drm/amd/display: document AMDGPU pre-defined transfer functions
Date: Mon, 25 Sep 2023 18:49:07 -0100 [thread overview]
Message-ID: <20230925194932.1329483-8-mwen@igalia.com> (raw)
In-Reply-To: <20230925194932.1329483-1-mwen@igalia.com>
Brief documentation about pre-defined transfer function usage on AMD
display driver and standardized EOTFs and inverse EOTFs.
v3:
- Document BT709 OETF (Pekka)
- Fix description of sRGB and pure power funcs (Pekka)
Co-developed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Melissa Wen <mwen@igalia.com>
---
.../amd/display/amdgpu_dm/amdgpu_dm_color.c | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
index d03bdb010e8b..14f9c02539c6 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -85,6 +85,45 @@ void amdgpu_dm_init_color_mod(void)
}
#ifdef AMD_PRIVATE_COLOR
+/* Pre-defined Transfer Functions (TF)
+ *
+ * AMD driver supports pre-defined mathematical functions for transferring
+ * between encoded values and optical/linear space. Depending on HW color caps,
+ * ROMs and curves built by the AMD color module support these transforms.
+ *
+ * The driver-specific color implementation exposes properties for pre-blending
+ * degamma TF, shaper TF (before 3D LUT), and blend(dpp.ogam) TF and
+ * post-blending regamma (mpc.ogam) TF. However, only pre-blending degamma
+ * supports ROM curves. AMD color module uses pre-defined coefficients to build
+ * curves for the other blocks. What can be done by each color block is
+ * described by struct dpp_color_capsand struct mpc_color_caps.
+ *
+ * AMD driver-specific color API exposes the following pre-defined transfer
+ * functions:
+ *
+ * - Linear/Unity: linear/identity relationship between pixel value and
+ * luminance value;
+ * - Gamma 2.2, Gamma 2.4, Gamma 2.6: pure power functions;
+ * - sRGB: 2.4: The piece-wise transfer function from IEC 61966-2-1:1999;
+ * - BT.709: has a linear segment in the bottom part and then a power function
+ * with a 0.45 (~1/2.22) gamma for the rest of the range; standardized by
+ * ITU-R BT.709-6;
+ * - PQ (Perceptual Quantizer): used for HDR display, allows luminance range
+ * capability of 0 to 10,000 nits; standardized by SMPTE ST 2084.
+ *
+ * In the driver-specific API, color block names attached to TF properties
+ * suggest the intention regarding non-linear encoding pixel's luminance
+ * values. As some newer encodings don't use gamma curve, we make encoding and
+ * decoding explicit by defining an enum list of transfer functions supported
+ * in terms of EOTF and inverse EOTF, where:
+ *
+ * - EOTF (electro-optical transfer function): is the transfer function to go
+ * from the encoded value to an optical (linear) value. De-gamma functions
+ * traditionally do this.
+ * - Inverse EOTF (simply the inverse of the EOTF): is usually intended to go
+ * from an optical/linear space (which might have been used for blending)
+ * back to the encoded values. Gamma functions traditionally do this.
+ */
static const char * const
amdgpu_transfer_function_names[] = {
[AMDGPU_TRANSFER_FUNCTION_DEFAULT] = "Default",
--
2.40.1
next prev parent reply other threads:[~2023-09-25 19:50 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-25 19:49 [PATCH v3 00/32] drm/amd/display: add AMD driver-specific properties for color mgmt Melissa Wen
2023-09-25 19:49 ` [PATCH v3 01/32] drm/drm_mode_object: increase max objects to accommodate new color props Melissa Wen
2023-09-25 19:49 ` [PATCH v3 02/32] drm/drm_property: make replace_property_blob_from_id a DRM helper Melissa Wen
2023-09-25 19:49 ` [PATCH v3 03/32] drm/drm_plane: track color mgmt changes per plane Melissa Wen
2023-09-25 19:49 ` [PATCH v3 04/32] drm/amd/display: add driver-specific property for plane degamma LUT Melissa Wen
2023-09-25 19:49 ` [PATCH v3 05/32] drm/amd/display: add plane degamma TF driver-specific property Melissa Wen
2023-09-25 19:49 ` [PATCH v3 06/32] drm/amd/display: explicitly define EOTF and inverse EOTF Melissa Wen
2023-09-25 19:49 ` Melissa Wen [this message]
2023-09-28 20:16 ` [PATCH v3 07/32] drm/amd/display: document AMDGPU pre-defined transfer functions Harry Wentland
2023-09-29 7:35 ` Pekka Paalanen
2023-09-29 13:08 ` Harry Wentland
2023-09-25 19:49 ` [PATCH v3 08/32] drm/amd/display: add plane HDR multiplier driver-specific property Melissa Wen
2023-09-25 19:49 ` [PATCH v3 09/32] drm/amd/display: add plane 3D LUT driver-specific properties Melissa Wen
2023-09-27 18:47 ` Harry Wentland
2023-10-03 16:17 ` Melissa Wen
2023-09-25 19:49 ` [PATCH v3 10/32] drm/amd/display: add plane shaper LUT and TF " Melissa Wen
2023-09-25 19:49 ` [PATCH v3 11/32] drm/amd/display: add plane blend " Melissa Wen
2023-09-25 19:49 ` [PATCH v3 12/32] drm/amd/display: add CRTC gamma TF driver-specific property Melissa Wen
2023-09-25 19:49 ` [PATCH v3 13/32] drm/amd/display: add comments to describe DM crtc color mgmt behavior Melissa Wen
2023-09-25 19:49 ` [PATCH v3 14/32] drm/amd/display: encapsulate atomic regamma operation Melissa Wen
2023-09-25 19:49 ` [PATCH v3 15/32] drm/amd/display: add CRTC gamma TF support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 16/32] drm/amd/display: set sdr_ref_white_level to 80 for out_transfer_func Melissa Wen
2023-09-25 19:49 ` [PATCH v3 17/32] drm/amd/display: mark plane as needing reset if color props change Melissa Wen
2023-09-25 19:49 ` [PATCH v3 18/32] drm/amd/display: decouple steps for mapping CRTC degamma to DC plane Melissa Wen
2023-09-25 19:49 ` [PATCH v3 19/32] drm/amd/display: add plane degamma TF and LUT support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 20/32] drm/amd/display: reject atomic commit if setting both plane and CRTC degamma Melissa Wen
2023-09-25 19:49 ` [PATCH v3 21/32] drm/amd/display: add dc_fixpt_from_s3132 helper Melissa Wen
2023-09-25 19:49 ` [PATCH v3 22/32] drm/amd/display: add HDR multiplier support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 23/32] drm/amd/display: add plane shaper LUT support Melissa Wen
2023-09-27 18:47 ` Harry Wentland
2023-09-25 19:49 ` [PATCH v3 24/32] drm/amd/display: add plane shaper TF support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 25/32] drm/amd/display: add plane 3D LUT support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 26/32] drm/amd/display: handle empty LUTs in __set_input_tf Melissa Wen
2023-09-25 19:49 ` [PATCH v3 27/32] drm/amd/display: add plane blend LUT and TF support Melissa Wen
2023-09-25 19:49 ` [PATCH v3 28/32] drm/amd/display: allow newer DC hardware to use degamma ROM for PQ/HLG Melissa Wen
2023-09-27 18:49 ` Harry Wentland
2023-09-25 19:49 ` [PATCH v3 29/32] drm/amd/display: copy 3D LUT settings from crtc state to stream_update Melissa Wen
2023-09-25 19:49 ` [PATCH v3 30/32] drm/amd/display: add plane CTM driver-specific property Melissa Wen
2023-09-25 19:49 ` [PATCH v3 31/32] drm/amd/display: add plane CTM support Melissa Wen
2023-09-27 18:52 ` Harry Wentland
2023-09-25 19:49 ` [PATCH v3 32/32] drm/amd/display: Add 3x4 CTM support for plane CTM Melissa Wen
2023-09-27 18:53 ` Harry Wentland
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