From b1a98cf89a695d36c414653634ea7ba91b6e701f Mon Sep 17 00:00:00 2001
From: Ma Hanghong <hanghong.ma@amd.com>
Date: Thu, 20 Oct 2022 11:46:56 -0400
Subject: [PATCH] drm/amd/display: Wrong colorimetry workaround
Git-commit: b1a98cf89a695d36c414653634ea7ba91b6e701f
Patch-mainline: v6.2-rc1
References: git-fixes

[Why]
For FreeSync HDR, native color space flag in AMD VSIF(BT.709) should be
used when intepreting content and color space flag in VSC or AVI
infoFrame should be ignored. However, it turned out some userspace
application still use color flag in VSC or AVI infoFrame which is
incorrect.

[How]
Transfer function is used when building the VSC and AVI infoFrame. Set
colorimetry to BT.709 when all the following match:

1. Pixel format is YCbCr;
2. In FreeSync 2 HDR, color is COLOR_SPACE_2020_YCBCR;
3. Transfer function is TRANSFER_FUNC_GAMMA_22;

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Ma Hanghong <hanghong.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c           | 5 ++++-
 drivers/gpu/drm/amd/display/dc/core/dc_resource.c           | 6 ++++++
 drivers/gpu/drm/amd/display/modules/inc/mod_info_packet.h   | 3 ++-
 .../gpu/drm/amd/display/modules/info_packet/info_packet.c   | 6 +++++-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 72aede3fcf9b..d14e57b19066 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5697,6 +5697,7 @@ create_stream_for_sink(struct amdgpu_dm_connector *aconnector,
 	bool scale = dm_state ? (dm_state->scaling != RMX_OFF) : false;
 	int mode_refresh;
 	int preferred_refresh = 0;
+	enum color_transfer_func tf = TRANSFER_FUNC_UNKNOWN;
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 	struct dsc_dec_dpcd_caps dsc_caps;
 #endif
@@ -5820,7 +5821,9 @@ create_stream_for_sink(struct amdgpu_dm_connector *aconnector,
 			if (stream->link->dpcd_caps.dprx_feature.bits.VSC_SDP_COLORIMETRY_SUPPORTED)
 				stream->use_vsc_sdp_for_colorimetry = true;
 		}
-		mod_build_vsc_infopacket(stream, &stream->vsc_infopacket, stream->output_color_space);
+		if (stream->out_transfer_func->tf == TRANSFER_FUNCTION_GAMMA22)
+			tf = TRANSFER_FUNC_GAMMA_22;
+		mod_build_vsc_infopacket(stream, &stream->vsc_infopacket, stream->output_color_space, tf);
 		aconnector->psr_skip_count = AMDGPU_DM_PSR_ENTRY_DELAY;
 
 	}
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index ba2d4347f722..d99f1c4b9584 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -3015,6 +3015,12 @@ static void set_avi_info_frame(
 		hdmi_info.bits.C0_C1   = COLORIMETRY_EXTENDED;
 	}
 
+	if (pixel_encoding && color_space == COLOR_SPACE_2020_YCBCR &&
+			stream->out_transfer_func->tf == TRANSFER_FUNCTION_GAMMA22) {
+		hdmi_info.bits.EC0_EC2 = 0;
+		hdmi_info.bits.C0_C1 = COLORIMETRY_ITU709;
+	}
+
 	/* TODO: un-hardcode aspect ratio */
 	aspect = stream->timing.aspect_ratio;
 
diff --git a/drivers/gpu/drm/amd/display/modules/inc/mod_info_packet.h b/drivers/gpu/drm/amd/display/modules/inc/mod_info_packet.h
index 1d8b746b02f2..edf5845f6a1f 100644
--- a/drivers/gpu/drm/amd/display/modules/inc/mod_info_packet.h
+++ b/drivers/gpu/drm/amd/display/modules/inc/mod_info_packet.h
@@ -35,7 +35,8 @@ struct mod_vrr_params;
 
 void mod_build_vsc_infopacket(const struct dc_stream_state *stream,
 		struct dc_info_packet *info_packet,
-		enum dc_color_space cs);
+		enum dc_color_space cs,
+		enum color_transfer_func tf);
 
 void mod_build_hf_vsif_infopacket(const struct dc_stream_state *stream,
 		struct dc_info_packet *info_packet);
diff --git a/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
index 27ceba9d6d65..69691058ab89 100644
--- a/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
+++ b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
@@ -132,7 +132,8 @@ enum ColorimetryYCCDP {
 
 void mod_build_vsc_infopacket(const struct dc_stream_state *stream,
 		struct dc_info_packet *info_packet,
-		enum dc_color_space cs)
+		enum dc_color_space cs,
+		enum color_transfer_func tf)
 {
 	unsigned int vsc_packet_revision = vsc_packet_undefined;
 	unsigned int i;
@@ -382,6 +383,9 @@ void mod_build_vsc_infopacket(const struct dc_stream_state *stream,
 				colorimetryFormat = ColorimetryYCC_DP_AdobeYCC;
 			else if (cs == COLOR_SPACE_2020_YCBCR)
 				colorimetryFormat = ColorimetryYCC_DP_ITU2020YCbCr;
+
+			if (cs == COLOR_SPACE_2020_YCBCR && tf == TRANSFER_FUNC_GAMMA_22)
+				colorimetryFormat = ColorimetryYCC_DP_ITU709;
 			break;
 
 		default:
-- 
2.43.0