[PATCH 2/3] drm/amd/display: Honor Broadcast RGB for BT.2020 RGB output

[Satyajit Roy]

From: Satyajit Roy <sroy14@xxxxxxxxxxxx>

amdgpu_dm_get_output_color_space() applies the Broadcast RGB connector
property to default RGB output, but always selects full-range output for
BT.2020 RGB. Consequently, explicitly selecting Limited has no effect on
the output CSC or AVI InfoFrame when HDR uses BT.2020 RGB.

Select COLOR_SPACE_2020_RGB_LIMITEDRANGE when the output encoding is RGB
and Broadcast RGB is Limited. Keep Automatic and Full at full range, and
leave YCbCr output unchanged.

Add KUnit coverage for limited-range RGB output through both BT.2020
connector colorspace values.

Fixes: 6eb4c13a3845 ("drm/amd/display: Support "Broadcast RGB" drm property")
Signed-off-by: Satyajit Roy <sroy14@xxxxxxxxxxxx>
---
 .../display/amdgpu_dm/amdgpu_dm_connector.c   | 10 +++--
 .../tests/amdgpu_dm_connector_test.c          | 37 +++++++++++++++++++
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index 8a35e4df13c..f2f6a2a0db9 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -758,10 +758,14 @@ amdgpu_dm_get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing,
 		break;
 	case DRM_MODE_COLORIMETRY_BT2020_RGB:
 	case DRM_MODE_COLORIMETRY_BT2020_YCC:
-		if (dc_crtc_timing->pixel_encoding == PIXEL_ENCODING_RGB)
-			color_space = COLOR_SPACE_2020_RGB_FULLRANGE;
-		else
+		if (dc_crtc_timing->pixel_encoding == PIXEL_ENCODING_RGB) {
+			if (connector_state->hdmi.broadcast_rgb == DRM_HDMI_BROADCAST_RGB_LIMITED)
+				color_space = COLOR_SPACE_2020_RGB_LIMITEDRANGE;
+			else
+				color_space = COLOR_SPACE_2020_RGB_FULLRANGE;
+		} else {
 			color_space = COLOR_SPACE_2020_YCBCR_LIMITED;
+		}
 		break;
 	case DRM_MODE_COLORIMETRY_DEFAULT: /* ITU601 */
 	default:
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
index 76334fb840d..29bbe9f7826 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
@@ -570,6 +570,23 @@ static void dm_test_output_color_space_bt2020_rgb(struct kunit *test)
 			(int)COLOR_SPACE_2020_RGB_FULLRANGE);
 }
 
+/**
+ * dm_test_output_color_space_bt2020_rgb_limited - Test limited BT.2020 RGB
+ * @test: The KUnit test context
+ */
+static void dm_test_output_color_space_bt2020_rgb_limited(struct kunit *test)
+{
+	struct dc_crtc_timing timing = {};
+	struct drm_connector_state state = {};
+
+	timing.pixel_encoding = PIXEL_ENCODING_RGB;
+	state.colorspace = DRM_MODE_COLORIMETRY_BT2020_RGB;
+	state.hdmi.broadcast_rgb = DRM_HDMI_BROADCAST_RGB_LIMITED;
+
+	KUNIT_EXPECT_EQ(test, (int)amdgpu_dm_get_output_color_space(&timing, &state),
+			(int)COLOR_SPACE_2020_RGB_LIMITEDRANGE);
+}
+
 /**
  * dm_test_output_color_space_bt2020_ycc - Test Output color space bt2020 ycc
  * @test: The KUnit test context
@@ -641,6 +658,24 @@ static void dm_test_output_color_space_bt2020_ycc_rgb_encoding(struct kunit *tes
 			(int)COLOR_SPACE_2020_RGB_FULLRANGE);
 }
 
+/**
+ * dm_test_output_color_space_bt2020_ycc_rgb_encoding_limited - Test limited
+ * BT.2020 RGB output selected through the BT.2020 YCC connector colorspace
+ * @test: The KUnit test context
+ */
+static void dm_test_output_color_space_bt2020_ycc_rgb_encoding_limited(struct kunit *test)
+{
+	struct dc_crtc_timing timing = {};
+	struct drm_connector_state state = {};
+
+	timing.pixel_encoding = PIXEL_ENCODING_RGB;
+	state.colorspace = DRM_MODE_COLORIMETRY_BT2020_YCC;
+	state.hdmi.broadcast_rgb = DRM_HDMI_BROADCAST_RGB_LIMITED;
+
+	KUNIT_EXPECT_EQ(test, (int)amdgpu_dm_get_output_color_space(&timing, &state),
+			(int)COLOR_SPACE_2020_RGB_LIMITEDRANGE);
+}
+
 /**
  * dm_test_output_color_space_bt2020_rgb_ycc_encoding - Test Output color space
  * bt2020 rgb with non-rgb pixel encoding falls back to limited ycbcr
@@ -8409,10 +8444,12 @@ static struct kunit_case amdgpu_dm_connector_tests[] = {
 	KUNIT_CASE(dm_test_output_color_space_bt709_y_only),
 	KUNIT_CASE(dm_test_output_color_space_oprgb),
 	KUNIT_CASE(dm_test_output_color_space_bt2020_rgb),
+	KUNIT_CASE(dm_test_output_color_space_bt2020_rgb_limited),
 	KUNIT_CASE(dm_test_output_color_space_bt2020_ycc),
 	KUNIT_CASE(dm_test_output_color_space_default_ycbcr709_y_only),
 	KUNIT_CASE(dm_test_output_color_space_default_ycbcr601),
 	KUNIT_CASE(dm_test_output_color_space_bt2020_ycc_rgb_encoding),
+	KUNIT_CASE(dm_test_output_color_space_bt2020_ycc_rgb_encoding_limited),
 	KUNIT_CASE(dm_test_output_color_space_bt2020_rgb_ycc_encoding),
 	/* Tests for amdgpu_dm_convert_dc_color_depth_into_bpc */
 	KUNIT_CASE(dm_test_convert_color_depth_bpc_mappings),
-- 
2.51.1