[PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

Exposes the pixel encoding as the DRM property "pixel encoding"
and the module parameter pixel_encoding.

The DRM property may take values "auto" (current behaviour
when a display is plugged in), "rgb" for RGB, or "ycbcr444" for
YCbCr 4:4:4.

The module parameter may only be set on boot and is of the format
[connector-name:]encoding[,...] where encoding is one of the
same values as are valid for the DRM property.

https://gitlab.freedesktop.org/drm/amd/-/issues/476
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c   |  33 +++
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.h   |   4 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h      |   8 +
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 247 ++++++++++++++++--
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |   1 +
 drivers/gpu/drm/amd/display/dc/core/dc.c      |  12 +-
 drivers/gpu/drm/amd/display/dc/dc_stream.h    |   2 +
 7 files changed, 289 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index d76172965199..37748f35c52b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -614,6 +614,31 @@ static const struct drm_prop_enum_list amdgpu_dither_enum_list[] =
 	{ AMDGPU_FMT_DITHER_ENABLE, "on" },
 };
 
+static const struct drm_prop_enum_list amdgpu_user_pixenc_list[] =
+{	{ AMDGPU_USER_PIXENC_AUTO, "auto" },
+	{ AMDGPU_USER_PIXENC_RGB, "rgb" },
+	{ AMDGPU_USER_PIXENC_YCBCR444, "ycbcr444" },
+};
+
+bool amdgpu_user_pixenc_from_name(
+	enum amdgpu_user_pixenc *user_pixenc,
+	const char *pixenc_name)
+{
+	/* user_pixenc only modified if name found */
+	bool found = false;
+	if (pixenc_name && (*pixenc_name != '\0')) {
+		const int sz = ARRAY_SIZE(amdgpu_user_pixenc_list);
+		int i;
+		for (i = 0; !found && i < sz; ++i) {
+			if (strcmp(pixenc_name, amdgpu_user_pixenc_list[i].name) == 0) {
+				*user_pixenc = amdgpu_user_pixenc_list[i].type;
+				found = true;
+			}
+		}
+	}
+	return found;
+}
+
 int amdgpu_display_modeset_create_props(struct amdgpu_device *adev)
 {
 	int sz;
@@ -666,6 +691,14 @@ int amdgpu_display_modeset_create_props(struct amdgpu_device *adev)
 						"abm level", 0, 4);
 		if (!adev->mode_info.abm_level_property)
 			return -ENOMEM;
+
+		sz = ARRAY_SIZE(amdgpu_user_pixenc_list);
+		adev->mode_info.pixel_encoding_property =
+			drm_property_create_enum(adev->ddev, 0,
+				"pixel encoding",
+				amdgpu_user_pixenc_list, sz);
+		if (!adev->mode_info.pixel_encoding_property)
+			return -ENOMEM;
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
index 3620b24785e1..72f82e3f4e32 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
@@ -45,4 +45,8 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
 				       struct drm_file *file_priv,
 				       const struct drm_mode_fb_cmd2 *mode_cmd);
 
+bool amdgpu_user_pixenc_from_name(
+	enum amdgpu_user_pixenc *user_pixenc,
+	const char *pixenc_name);
+
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
index 37ba07e2feb5..3c21ecf3d259 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
@@ -123,6 +123,12 @@ enum amdgpu_flip_status {
 	AMDGPU_FLIP_SUBMITTED
 };
 
+enum amdgpu_user_pixenc {
+	AMDGPU_USER_PIXENC_AUTO,
+	AMDGPU_USER_PIXENC_RGB,
+	AMDGPU_USER_PIXENC_YCBCR444
+};
+
 #define AMDGPU_MAX_I2C_BUS 16
 
 /* amdgpu gpio-based i2c
@@ -333,6 +339,8 @@ struct amdgpu_mode_info {
 	struct drm_property *dither_property;
 	/* Adaptive Backlight Modulation (power feature) */
 	struct drm_property *abm_level_property;
+	/* User HDMI pixel encoding override */
+	struct drm_property *pixel_encoding_property;
 	/* hardcoded DFP edid from BIOS */
 	struct edid *bios_hardcoded_edid;
 	int bios_hardcoded_edid_size;
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 b51c527a3f0d..8901271d1902 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -158,7 +158,6 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector);
 static int amdgpu_dm_atomic_commit(struct drm_device *dev,
 				   struct drm_atomic_state *state,
 				   bool nonblock);
-
 static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state);
 
 static int amdgpu_dm_atomic_check(struct drm_device *dev,
@@ -172,6 +171,13 @@ static bool amdgpu_dm_psr_enable(struct dc_stream_state *stream);
 static bool amdgpu_dm_link_setup_psr(struct dc_stream_state *stream);
 static bool amdgpu_dm_psr_disable(struct dc_stream_state *stream);
 
+/**
+ * DOC: pixel_encoding (string)
+ * Specify the initial pixel encoding used by a connector.
+ */
+static char amdgpu_pixel_encoding[MAX_INPUT];
+MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
+module_param_string(pixel_encoding, amdgpu_pixel_encoding, sizeof(amdgpu_pixel_encoding), 0444);
 
 /*
  * dm_vblank_get_counter
@@ -4214,6 +4220,103 @@ static bool adjust_colour_depth_from_display_info(
 	return false;
 }
 
+
+/* convert an amdgpu_user_pixenc to a dc_pixel_encoding */
+static bool drm_prop_to_dc_pixel_encoding(
+	enum dc_pixel_encoding *dc_pixenc,
+	enum amdgpu_user_pixenc user_pixenc)
+{
+	bool ret = false;
+	switch(user_pixenc) {
+	case AMDGPU_USER_PIXENC_AUTO:
+		*dc_pixenc = PIXEL_ENCODING_UNDEFINED;
+		ret = true;
+		break;
+	case AMDGPU_USER_PIXENC_RGB:
+		*dc_pixenc = PIXEL_ENCODING_RGB;
+		ret = true;
+		break;
+	case AMDGPU_USER_PIXENC_YCBCR444:
+		*dc_pixenc = PIXEL_ENCODING_YCBCR444;
+		ret = true;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+
+/* convert an dc_pixel_encoding to a amdgpu_user_pixenc */
+static enum amdgpu_user_pixenc dc_pixel_encoding_to_drm_prop(
+	enum dc_pixel_encoding pixel_encoding)
+{
+	enum amdgpu_user_pixenc user_pixenc = AMDGPU_USER_PIXENC_AUTO;
+	switch(pixel_encoding) {
+	case PIXEL_ENCODING_RGB:
+		user_pixenc = AMDGPU_USER_PIXENC_RGB;
+		break;
+	case PIXEL_ENCODING_YCBCR444:
+		user_pixenc = AMDGPU_USER_PIXENC_YCBCR444;
+		break;
+	default:
+		break;
+	}
+	return user_pixenc;
+}
+
+/*
+ * Tries to read 'pixel_encoding' from the pixel_encoding DRM property on
+ * 'state'. Returns true if a supported, acceptable, non-undefined value is
+ * found; false otherwise. Only modifies 'pixel_encoding' if returning true.
+ */
+bool get_connector_state_pixel_encoding(
+	enum dc_pixel_encoding *pixel_encoding,
+	const struct drm_connector_state *state,
+	u32 color_formats)
+{
+	bool ret = false;
+	struct dm_connector_state *dm_state;
+
+	if (!(dm_state = to_dm_connector_state(state))) {
+		return false;
+	}
+
+	/* check encoding is supported */
+	switch (dm_state->pixel_encoding) {
+	case PIXEL_ENCODING_RGB:
+		ret = (color_formats & DRM_COLOR_FORMAT_RGB444);
+		break;
+	case PIXEL_ENCODING_YCBCR444:
+		ret = (color_formats & DRM_COLOR_FORMAT_YCRCB444);
+		break;
+	default:
+		break;
+	}
+
+	if(ret)
+		*pixel_encoding = dm_state->pixel_encoding;
+
+	return ret;
+}
+
+/*
+ * Writes 'pixel_encoding' to the pixel_encoding DRM property on 'state', if
+ * the enum value is valid and supported; otherwise writes
+ * PIXEL_ENCODING_UNDEFINED which corresponds to the "auto" property state.
+ */
+void set_connector_state_pixel_encoding(
+	const struct drm_connector_state *state,
+	enum dc_pixel_encoding pixel_encoding)
+{
+	struct dm_connector_state *dm_state;
+
+	if (!(dm_state = to_dm_connector_state(state)))
+		return;
+
+	dm_state->pixel_encoding = pixel_encoding;
+}
+
 static void fill_stream_properties_from_drm_display_mode(
 	struct dc_stream_state *stream,
 	const struct drm_display_mode *mode_in,
@@ -4235,18 +4338,20 @@ static void fill_stream_properties_from_drm_display_mode(
 	timing_out->h_border_right = 0;
 	timing_out->v_border_top = 0;
 	timing_out->v_border_bottom = 0;
-	/* TODO: un-hardcode */
-	if (drm_mode_is_420_only(info, mode_in)
-			&& stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
-		timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
-	else if (drm_mode_is_420_also(info, mode_in)
-			&& aconnector->force_yuv420_output)
-		timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
-	else if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
-			&& stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
-		timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
-	else
-		timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
+
+	if (!get_connector_state_pixel_encoding(&timing_out->pixel_encoding,
+		connector_state, connector->display_info.color_formats)) {
+		/* auto-select a pixel encoding */
+		if (drm_mode_is_420_only(info, mode_in) && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
+			timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
+		else if (drm_mode_is_420_also(info, mode_in) && aconnector->force_yuv420_output)
+			timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
+		else if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
+				&& stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
+			timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
+		else
+			timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
+	}
 
 	timing_out->timing_3d_format = TIMING_3D_FORMAT_NONE;
 	timing_out->display_color_depth = convert_color_depth_from_display_info(
@@ -4294,6 +4399,7 @@ static void fill_stream_properties_from_drm_display_mode(
 
 	stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
 	stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
+
 	if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A) {
 		if (!adjust_colour_depth_from_display_info(timing_out, info) &&
 		    drm_mode_is_420_also(info, mode_in) &&
@@ -4302,6 +4408,9 @@ static void fill_stream_properties_from_drm_display_mode(
 			adjust_colour_depth_from_display_info(timing_out, info);
 		}
 	}
+
+	/* write back final choice of pixel encoding */
+	set_connector_state_pixel_encoding(connector_state, timing_out->pixel_encoding);
 }
 
 static void fill_audio_info(struct audio_info *audio_info,
@@ -4818,6 +4927,9 @@ int amdgpu_dm_connector_atomic_set_property(struct drm_connector *connector,
 	} else if (property == adev->mode_info.abm_level_property) {
 		dm_new_state->abm_level = val;
 		ret = 0;
+	} else if (property == adev->mode_info.pixel_encoding_property) {
+		if(drm_prop_to_dc_pixel_encoding(&dm_new_state->pixel_encoding, val))
+			ret = 0;
 	}
 
 	return ret;
@@ -4863,6 +4975,9 @@ int amdgpu_dm_connector_atomic_get_property(struct drm_connector *connector,
 	} else if (property == adev->mode_info.abm_level_property) {
 		*val = dm_state->abm_level;
 		ret = 0;
+	} else if (property == adev->mode_info.pixel_encoding_property) {
+		*val = dc_pixel_encoding_to_drm_prop(dm_state->pixel_encoding);
+		ret = 0;
 	}
 
 	return ret;
@@ -4912,6 +5027,50 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
 	kfree(connector);
 }
 
+
+/*
+ * Returns the default pixel encoding, depending on the pixel_encoding
+ * module parameter if given.
+ */
+static enum dc_pixel_encoding pixel_encoding_reset(
+	const struct drm_connector *connector)
+{
+	char *param_str = NULL;
+	char *param_str_ptr = NULL;
+	char *param_item = NULL;
+	char *param_item_sep = NULL;
+	char *pixenc_mode = NULL;
+	enum amdgpu_user_pixenc user_pixenc;
+	enum dc_pixel_encoding pixel_encoding = PIXEL_ENCODING_UNDEFINED;
+
+	/* default in absence of module param */
+	if (*amdgpu_pixel_encoding == '\0')
+		return PIXEL_ENCODING_UNDEFINED;
+
+	/* decode param string */
+	param_str = kstrdup(amdgpu_pixel_encoding, GFP_KERNEL);
+	param_str_ptr = param_str;
+	while ((param_item = strsep(&param_str_ptr, ","))) {
+		param_item_sep = strchr(param_item, ':');
+		if (param_item_sep) {
+			if (strncmp(connector->name, param_item,
+				   param_item_sep - param_item) == 0) {
+				   pixenc_mode = param_item_sep + 1;
+				   break;
+			}
+		} else
+			pixenc_mode = param_item;
+	}
+
+	/* compare mode string and set */
+	if (amdgpu_user_pixenc_from_name(&user_pixenc, pixenc_mode)) {
+		drm_prop_to_dc_pixel_encoding(&pixel_encoding, user_pixenc);
+	}
+
+	kfree(param_str);
+	return pixel_encoding;
+}
+
 void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
 {
 	struct dm_connector_state *state =
@@ -4934,7 +5093,7 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
 		state->pbn = 0;
 		if (connector->connector_type == DRM_MODE_CONNECTOR_eDP)
 			state->abm_level = amdgpu_dm_abm_level;
-
+		state->pixel_encoding = pixel_encoding_reset(connector);
 		__drm_atomic_helper_connector_reset(connector, &state->base);
 	}
 }
@@ -4961,6 +5120,7 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector)
 	new_state->underscan_vborder = state->underscan_vborder;
 	new_state->vcpi_slots = state->vcpi_slots;
 	new_state->pbn = state->pbn;
+	new_state->pixel_encoding = state->pixel_encoding;
 	return &new_state->base;
 }
 
@@ -6175,6 +6335,7 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
 	return amdgpu_dm_connector->num_modes;
 }
 
+
 void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 				     struct amdgpu_dm_connector *aconnector,
 				     int connector_type,
@@ -6263,6 +6424,12 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 		if (adev->dm.hdcp_workqueue)
 			drm_connector_attach_content_protection_property(&aconnector->base, true);
 #endif
+
+		if (adev->mode_info.pixel_encoding_property) {
+			drm_object_attach_property(&aconnector->base.base,
+				adev->mode_info.pixel_encoding_property, 0);
+			DRM_DEBUG_DRIVER("amdgpu: attached pixel encoding drm property");
+		}
 	}
 }
 
@@ -7332,6 +7499,37 @@ static int amdgpu_dm_atomic_commit(struct drm_device *dev,
 	/*TODO Handle EINTR, reenable IRQ*/
 }
 
+static void update_stream_for_pixel_encoding(
+	struct dc_stream_update *stream_update,
+	struct drm_connector *connector,
+	struct dm_crtc_state *dm_old_crtc_state,
+	struct dm_crtc_state *dm_new_crtc_state,
+	struct dm_connector_state *dm_new_con_state)
+{
+	struct amdgpu_dm_connector *aconnector =
+		to_amdgpu_dm_connector(connector);
+	struct dc_stream_state *new_stream = NULL;
+	if (aconnector)
+		new_stream = create_validate_stream_for_sink(
+			aconnector,
+			&dm_new_crtc_state->base.mode,
+			dm_new_con_state,
+			dm_old_crtc_state->stream);
+	if (new_stream) {
+		dm_new_crtc_state->stream->timing =
+			new_stream->timing;
+		stream_update->timing_for_pixel_encoding =
+			&dm_new_crtc_state->stream->timing;
+
+		dm_new_crtc_state->stream->output_color_space =
+			new_stream->output_color_space;
+		stream_update->output_color_space =
+			&dm_new_crtc_state->stream->output_color_space;
+
+		dc_stream_release(new_stream);
+	}
+}
+
 /**
  * amdgpu_dm_atomic_commit_tail() - AMDgpu DM's commit tail implementation.
  * @state: The atomic state to commit
@@ -7508,7 +7706,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		struct dc_stream_update stream_update;
 		struct dc_info_packet hdr_packet;
 		struct dc_stream_status *status = NULL;
-		bool abm_changed, hdr_changed, scaling_changed;
+		bool abm_changed, hdr_changed, scaling_changed, pixenc_changed;
 
 		memset(&dummy_updates, 0, sizeof(dummy_updates));
 		memset(&stream_update, 0, sizeof(stream_update));
@@ -7534,7 +7732,10 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		hdr_changed =
 			is_hdr_metadata_different(old_con_state, new_con_state);
 
-		if (!scaling_changed && !abm_changed && !hdr_changed)
+		pixenc_changed = dm_new_con_state->pixel_encoding !=
+				 dm_old_con_state->pixel_encoding;
+
+		if (!scaling_changed && !abm_changed && !hdr_changed && !pixenc_changed)
 			continue;
 
 		stream_update.stream = dm_new_crtc_state->stream;
@@ -7557,6 +7758,13 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 			stream_update.hdr_static_metadata = &hdr_packet;
 		}
 
+		if (pixenc_changed) {
+			update_stream_for_pixel_encoding(&stream_update,
+				connector,
+				dm_old_crtc_state, dm_new_crtc_state,
+				dm_new_con_state);
+		}
+
 		status = dc_stream_get_status(dm_new_crtc_state->stream);
 		WARN_ON(!status);
 		WARN_ON(!status->plane_count);
@@ -7911,7 +8119,6 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm,
 							     &new_crtc_state->mode,
 							     dm_new_conn_state,
 							     dm_old_crtc_state->stream);
-
 		/*
 		 * we can have no stream on ACTION_SET if a display
 		 * was disconnected during S3, in this case it is not an
@@ -8578,6 +8785,12 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		if (dm_old_con_state->abm_level !=
 		    dm_new_con_state->abm_level)
 			new_crtc_state->connectors_changed = true;
+
+		if (dm_old_con_state->pixel_encoding !=
+		    dm_new_con_state->pixel_encoding) {
+			new_crtc_state->connectors_changed = true;
+			new_crtc_state->mode_changed = true;
+		}
 	}
 
 #if defined(CONFIG_DRM_AMD_DC_DCN)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index dd1559c743c2..e46bdd279d0f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -450,6 +450,7 @@ struct dm_connector_state {
 	uint8_t abm_level;
 	int vcpi_slots;
 	uint64_t pbn;
+	enum dc_pixel_encoding pixel_encoding;
 };
 
 #define to_dm_connector_state(x)\
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 92eb1ca1634f..24743ee9d9da 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1881,6 +1881,11 @@ static enum surface_update_type check_update_surfaces_for_stream(
 
 		if (stream_update->output_csc_transform || stream_update->output_color_space)
 			su_flags->bits.out_csc = 1;
+
+		if (stream_update->timing_for_pixel_encoding) {
+			su_flags->bits.pixel_encoding = 1;
+			elevate_update_type(&overall_type, UPDATE_TYPE_FULL);
+		}
 	}
 
 	for (i = 0 ; i < surface_count; i++) {
@@ -2183,6 +2188,10 @@ static void copy_stream_update_to_stream(struct dc *dc,
 			update->dsc_config = NULL;
 		}
 	}
+
+	if (update->timing_for_pixel_encoding) {
+		stream->timing = *update->timing_for_pixel_encoding;
+	}
 }
 
 static void commit_planes_do_stream_update(struct dc *dc,
@@ -2211,7 +2220,8 @@ static void commit_planes_do_stream_update(struct dc *dc,
 			if ((stream_update->hdr_static_metadata && !stream->use_dynamic_meta) ||
 					stream_update->vrr_infopacket ||
 					stream_update->vsc_infopacket ||
-					stream_update->vsp_infopacket) {
+					stream_update->vsp_infopacket ||
+					stream_update->timing_for_pixel_encoding) {
 				resource_build_info_frame(pipe_ctx);
 				dc->hwss.update_info_frame(pipe_ctx);
 			}
diff --git a/drivers/gpu/drm/amd/display/dc/dc_stream.h b/drivers/gpu/drm/amd/display/dc/dc_stream.h
index d9888f316da6..0e1ef24d8855 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_stream.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_stream.h
@@ -126,6 +126,7 @@ union stream_update_flags {
 		uint32_t gamut_remap:1;
 		uint32_t wb_update:1;
 		uint32_t dsc_changed : 1;
+		uint32_t pixel_encoding:1;
 	} bits;
 
 	uint32_t raw;
@@ -262,6 +263,7 @@ struct dc_stream_update {
 
 	struct dc_writeback_update *wb_update;
 	struct dc_dsc_config *dsc_config;
+	struct dc_crtc_timing *timing_for_pixel_encoding;
 #if defined(CONFIG_DRM_AMD_DC_DCN3_0)
 	struct dc_transfer_func *func_shaper;
 	struct dc_3dlut *lut3d_func;
-- 
2.26.2

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amd-gfx@lists.freedesktop.org
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Alex Deucher]

On Tue, Sep 22, 2020 at 3:34 PM James Ettle <james@ettle.org.uk> wrote:
>
> Exposes the pixel encoding as the DRM property "pixel encoding"
> and the module parameter pixel_encoding.
>
> The DRM property may take values "auto" (current behaviour
> when a display is plugged in), "rgb" for RGB, or "ycbcr444" for
> YCbCr 4:4:4.
>
> The module parameter may only be set on boot and is of the format
> [connector-name:]encoding[,...] where encoding is one of the
> same values as are valid for the DRM property.
>
> https://gitlab.freedesktop.org/drm/amd/-/issues/476
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_display.c   |  33 +++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_display.h   |   4 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h      |   8 +
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 247 ++++++++++++++++--
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |   1 +
>  drivers/gpu/drm/amd/display/dc/core/dc.c      |  12 +-
>  drivers/gpu/drm/amd/display/dc/dc_stream.h    |   2 +
>  7 files changed, 289 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> index d76172965199..37748f35c52b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> @@ -614,6 +614,31 @@ static const struct drm_prop_enum_list amdgpu_dither_enum_list[] =
>         { AMDGPU_FMT_DITHER_ENABLE, "on" },
>  };
>
> +static const struct drm_prop_enum_list amdgpu_user_pixenc_list[] =
> +{      { AMDGPU_USER_PIXENC_AUTO, "auto" },
> +       { AMDGPU_USER_PIXENC_RGB, "rgb" },
> +       { AMDGPU_USER_PIXENC_YCBCR444, "ycbcr444" },
> +};
> +
> +bool amdgpu_user_pixenc_from_name(
> +       enum amdgpu_user_pixenc *user_pixenc,
> +       const char *pixenc_name)
> +{
> +       /* user_pixenc only modified if name found */
> +       bool found = false;
> +       if (pixenc_name && (*pixenc_name != '\0')) {
> +               const int sz = ARRAY_SIZE(amdgpu_user_pixenc_list);
> +               int i;
> +               for (i = 0; !found && i < sz; ++i) {
> +                       if (strcmp(pixenc_name, amdgpu_user_pixenc_list[i].name) == 0) {
> +                               *user_pixenc = amdgpu_user_pixenc_list[i].type;
> +                               found = true;
> +                       }
> +               }
> +       }
> +       return found;
> +}
> +
>  int amdgpu_display_modeset_create_props(struct amdgpu_device *adev)
>  {
>         int sz;
> @@ -666,6 +691,14 @@ int amdgpu_display_modeset_create_props(struct amdgpu_device *adev)
>                                                 "abm level", 0, 4);
>                 if (!adev->mode_info.abm_level_property)
>                         return -ENOMEM;
> +
> +               sz = ARRAY_SIZE(amdgpu_user_pixenc_list);
> +               adev->mode_info.pixel_encoding_property =
> +                       drm_property_create_enum(adev->ddev, 0,
> +                               "pixel encoding",
> +                               amdgpu_user_pixenc_list, sz);
> +               if (!adev->mode_info.pixel_encoding_property)
> +                       return -ENOMEM;
>         }
>
>         return 0;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
> index 3620b24785e1..72f82e3f4e32 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
> @@ -45,4 +45,8 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
>                                        struct drm_file *file_priv,
>                                        const struct drm_mode_fb_cmd2 *mode_cmd);
>
> +bool amdgpu_user_pixenc_from_name(
> +       enum amdgpu_user_pixenc *user_pixenc,
> +       const char *pixenc_name);
> +
>  #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> index 37ba07e2feb5..3c21ecf3d259 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> @@ -123,6 +123,12 @@ enum amdgpu_flip_status {
>         AMDGPU_FLIP_SUBMITTED
>  };
>
> +enum amdgpu_user_pixenc {
> +       AMDGPU_USER_PIXENC_AUTO,
> +       AMDGPU_USER_PIXENC_RGB,
> +       AMDGPU_USER_PIXENC_YCBCR444
> +};
> +
>  #define AMDGPU_MAX_I2C_BUS 16
>
>  /* amdgpu gpio-based i2c
> @@ -333,6 +339,8 @@ struct amdgpu_mode_info {
>         struct drm_property *dither_property;
>         /* Adaptive Backlight Modulation (power feature) */
>         struct drm_property *abm_level_property;
> +       /* User HDMI pixel encoding override */
> +       struct drm_property *pixel_encoding_property;
>         /* hardcoded DFP edid from BIOS */
>         struct edid *bios_hardcoded_edid;
>         int bios_hardcoded_edid_size;
> 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 b51c527a3f0d..8901271d1902 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -158,7 +158,6 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector);
>  static int amdgpu_dm_atomic_commit(struct drm_device *dev,
>                                    struct drm_atomic_state *state,
>                                    bool nonblock);
> -
>  static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state);
>
>  static int amdgpu_dm_atomic_check(struct drm_device *dev,
> @@ -172,6 +171,13 @@ static bool amdgpu_dm_psr_enable(struct dc_stream_state *stream);
>  static bool amdgpu_dm_link_setup_psr(struct dc_stream_state *stream);
>  static bool amdgpu_dm_psr_disable(struct dc_stream_state *stream);
>
> +/**
> + * DOC: pixel_encoding (string)
> + * Specify the initial pixel encoding used by a connector.
> + */
> +static char amdgpu_pixel_encoding[MAX_INPUT];
> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
> +module_param_string(pixel_encoding, amdgpu_pixel_encoding, sizeof(amdgpu_pixel_encoding), 0444);

You can drop this part.  We don't need a module parameter if we have a
kms property.

Alex


>
>  /*
>   * dm_vblank_get_counter
> @@ -4214,6 +4220,103 @@ static bool adjust_colour_depth_from_display_info(
>         return false;
>  }
>
> +
> +/* convert an amdgpu_user_pixenc to a dc_pixel_encoding */
> +static bool drm_prop_to_dc_pixel_encoding(
> +       enum dc_pixel_encoding *dc_pixenc,
> +       enum amdgpu_user_pixenc user_pixenc)
> +{
> +       bool ret = false;
> +       switch(user_pixenc) {
> +       case AMDGPU_USER_PIXENC_AUTO:
> +               *dc_pixenc = PIXEL_ENCODING_UNDEFINED;
> +               ret = true;
> +               break;
> +       case AMDGPU_USER_PIXENC_RGB:
> +               *dc_pixenc = PIXEL_ENCODING_RGB;
> +               ret = true;
> +               break;
> +       case AMDGPU_USER_PIXENC_YCBCR444:
> +               *dc_pixenc = PIXEL_ENCODING_YCBCR444;
> +               ret = true;
> +               break;
> +       default:
> +               break;
> +       }
> +       return ret;
> +}
> +
> +
> +/* convert an dc_pixel_encoding to a amdgpu_user_pixenc */
> +static enum amdgpu_user_pixenc dc_pixel_encoding_to_drm_prop(
> +       enum dc_pixel_encoding pixel_encoding)
> +{
> +       enum amdgpu_user_pixenc user_pixenc = AMDGPU_USER_PIXENC_AUTO;
> +       switch(pixel_encoding) {
> +       case PIXEL_ENCODING_RGB:
> +               user_pixenc = AMDGPU_USER_PIXENC_RGB;
> +               break;
> +       case PIXEL_ENCODING_YCBCR444:
> +               user_pixenc = AMDGPU_USER_PIXENC_YCBCR444;
> +               break;
> +       default:
> +               break;
> +       }
> +       return user_pixenc;
> +}
> +
> +/*
> + * Tries to read 'pixel_encoding' from the pixel_encoding DRM property on
> + * 'state'. Returns true if a supported, acceptable, non-undefined value is
> + * found; false otherwise. Only modifies 'pixel_encoding' if returning true.
> + */
> +bool get_connector_state_pixel_encoding(
> +       enum dc_pixel_encoding *pixel_encoding,
> +       const struct drm_connector_state *state,
> +       u32 color_formats)
> +{
> +       bool ret = false;
> +       struct dm_connector_state *dm_state;
> +
> +       if (!(dm_state = to_dm_connector_state(state))) {
> +               return false;
> +       }
> +
> +       /* check encoding is supported */
> +       switch (dm_state->pixel_encoding) {
> +       case PIXEL_ENCODING_RGB:
> +               ret = (color_formats & DRM_COLOR_FORMAT_RGB444);
> +               break;
> +       case PIXEL_ENCODING_YCBCR444:
> +               ret = (color_formats & DRM_COLOR_FORMAT_YCRCB444);
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       if(ret)
> +               *pixel_encoding = dm_state->pixel_encoding;
> +
> +       return ret;
> +}
> +
> +/*
> + * Writes 'pixel_encoding' to the pixel_encoding DRM property on 'state', if
> + * the enum value is valid and supported; otherwise writes
> + * PIXEL_ENCODING_UNDEFINED which corresponds to the "auto" property state.
> + */
> +void set_connector_state_pixel_encoding(
> +       const struct drm_connector_state *state,
> +       enum dc_pixel_encoding pixel_encoding)
> +{
> +       struct dm_connector_state *dm_state;
> +
> +       if (!(dm_state = to_dm_connector_state(state)))
> +               return;
> +
> +       dm_state->pixel_encoding = pixel_encoding;
> +}
> +
>  static void fill_stream_properties_from_drm_display_mode(
>         struct dc_stream_state *stream,
>         const struct drm_display_mode *mode_in,
> @@ -4235,18 +4338,20 @@ static void fill_stream_properties_from_drm_display_mode(
>         timing_out->h_border_right = 0;
>         timing_out->v_border_top = 0;
>         timing_out->v_border_bottom = 0;
> -       /* TODO: un-hardcode */
> -       if (drm_mode_is_420_only(info, mode_in)
> -                       && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
> -               timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
> -       else if (drm_mode_is_420_also(info, mode_in)
> -                       && aconnector->force_yuv420_output)
> -               timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
> -       else if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
> -                       && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
> -               timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
> -       else
> -               timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
> +
> +       if (!get_connector_state_pixel_encoding(&timing_out->pixel_encoding,
> +               connector_state, connector->display_info.color_formats)) {
> +               /* auto-select a pixel encoding */
> +               if (drm_mode_is_420_only(info, mode_in) && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
> +                       timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
> +               else if (drm_mode_is_420_also(info, mode_in) && aconnector->force_yuv420_output)
> +                       timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
> +               else if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
> +                               && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
> +                       timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
> +               else
> +                       timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
> +       }
>
>         timing_out->timing_3d_format = TIMING_3D_FORMAT_NONE;
>         timing_out->display_color_depth = convert_color_depth_from_display_info(
> @@ -4294,6 +4399,7 @@ static void fill_stream_properties_from_drm_display_mode(
>
>         stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
>         stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
> +
>         if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A) {
>                 if (!adjust_colour_depth_from_display_info(timing_out, info) &&
>                     drm_mode_is_420_also(info, mode_in) &&
> @@ -4302,6 +4408,9 @@ static void fill_stream_properties_from_drm_display_mode(
>                         adjust_colour_depth_from_display_info(timing_out, info);
>                 }
>         }
> +
> +       /* write back final choice of pixel encoding */
> +       set_connector_state_pixel_encoding(connector_state, timing_out->pixel_encoding);
>  }
>
>  static void fill_audio_info(struct audio_info *audio_info,
> @@ -4818,6 +4927,9 @@ int amdgpu_dm_connector_atomic_set_property(struct drm_connector *connector,
>         } else if (property == adev->mode_info.abm_level_property) {
>                 dm_new_state->abm_level = val;
>                 ret = 0;
> +       } else if (property == adev->mode_info.pixel_encoding_property) {
> +               if(drm_prop_to_dc_pixel_encoding(&dm_new_state->pixel_encoding, val))
> +                       ret = 0;
>         }
>
>         return ret;
> @@ -4863,6 +4975,9 @@ int amdgpu_dm_connector_atomic_get_property(struct drm_connector *connector,
>         } else if (property == adev->mode_info.abm_level_property) {
>                 *val = dm_state->abm_level;
>                 ret = 0;
> +       } else if (property == adev->mode_info.pixel_encoding_property) {
> +               *val = dc_pixel_encoding_to_drm_prop(dm_state->pixel_encoding);
> +               ret = 0;
>         }
>
>         return ret;
> @@ -4912,6 +5027,50 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
>         kfree(connector);
>  }
>
> +
> +/*
> + * Returns the default pixel encoding, depending on the pixel_encoding
> + * module parameter if given.
> + */
> +static enum dc_pixel_encoding pixel_encoding_reset(
> +       const struct drm_connector *connector)
> +{
> +       char *param_str = NULL;
> +       char *param_str_ptr = NULL;
> +       char *param_item = NULL;
> +       char *param_item_sep = NULL;
> +       char *pixenc_mode = NULL;
> +       enum amdgpu_user_pixenc user_pixenc;
> +       enum dc_pixel_encoding pixel_encoding = PIXEL_ENCODING_UNDEFINED;
> +
> +       /* default in absence of module param */
> +       if (*amdgpu_pixel_encoding == '\0')
> +               return PIXEL_ENCODING_UNDEFINED;
> +
> +       /* decode param string */
> +       param_str = kstrdup(amdgpu_pixel_encoding, GFP_KERNEL);
> +       param_str_ptr = param_str;
> +       while ((param_item = strsep(&param_str_ptr, ","))) {
> +               param_item_sep = strchr(param_item, ':');
> +               if (param_item_sep) {
> +                       if (strncmp(connector->name, param_item,
> +                                  param_item_sep - param_item) == 0) {
> +                                  pixenc_mode = param_item_sep + 1;
> +                                  break;
> +                       }
> +               } else
> +                       pixenc_mode = param_item;
> +       }
> +
> +       /* compare mode string and set */
> +       if (amdgpu_user_pixenc_from_name(&user_pixenc, pixenc_mode)) {
> +               drm_prop_to_dc_pixel_encoding(&pixel_encoding, user_pixenc);
> +       }
> +
> +       kfree(param_str);
> +       return pixel_encoding;
> +}
> +
>  void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
>  {
>         struct dm_connector_state *state =
> @@ -4934,7 +5093,7 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
>                 state->pbn = 0;
>                 if (connector->connector_type == DRM_MODE_CONNECTOR_eDP)
>                         state->abm_level = amdgpu_dm_abm_level;
> -
> +               state->pixel_encoding = pixel_encoding_reset(connector);
>                 __drm_atomic_helper_connector_reset(connector, &state->base);
>         }
>  }
> @@ -4961,6 +5120,7 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector)
>         new_state->underscan_vborder = state->underscan_vborder;
>         new_state->vcpi_slots = state->vcpi_slots;
>         new_state->pbn = state->pbn;
> +       new_state->pixel_encoding = state->pixel_encoding;
>         return &new_state->base;
>  }
>
> @@ -6175,6 +6335,7 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
>         return amdgpu_dm_connector->num_modes;
>  }
>
> +
>  void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
>                                      struct amdgpu_dm_connector *aconnector,
>                                      int connector_type,
> @@ -6263,6 +6424,12 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
>                 if (adev->dm.hdcp_workqueue)
>                         drm_connector_attach_content_protection_property(&aconnector->base, true);
>  #endif
> +
> +               if (adev->mode_info.pixel_encoding_property) {
> +                       drm_object_attach_property(&aconnector->base.base,
> +                               adev->mode_info.pixel_encoding_property, 0);
> +                       DRM_DEBUG_DRIVER("amdgpu: attached pixel encoding drm property");
> +               }
>         }
>  }
>
> @@ -7332,6 +7499,37 @@ static int amdgpu_dm_atomic_commit(struct drm_device *dev,
>         /*TODO Handle EINTR, reenable IRQ*/
>  }
>
> +static void update_stream_for_pixel_encoding(
> +       struct dc_stream_update *stream_update,
> +       struct drm_connector *connector,
> +       struct dm_crtc_state *dm_old_crtc_state,
> +       struct dm_crtc_state *dm_new_crtc_state,
> +       struct dm_connector_state *dm_new_con_state)
> +{
> +       struct amdgpu_dm_connector *aconnector =
> +               to_amdgpu_dm_connector(connector);
> +       struct dc_stream_state *new_stream = NULL;
> +       if (aconnector)
> +               new_stream = create_validate_stream_for_sink(
> +                       aconnector,
> +                       &dm_new_crtc_state->base.mode,
> +                       dm_new_con_state,
> +                       dm_old_crtc_state->stream);
> +       if (new_stream) {
> +               dm_new_crtc_state->stream->timing =
> +                       new_stream->timing;
> +               stream_update->timing_for_pixel_encoding =
> +                       &dm_new_crtc_state->stream->timing;
> +
> +               dm_new_crtc_state->stream->output_color_space =
> +                       new_stream->output_color_space;
> +               stream_update->output_color_space =
> +                       &dm_new_crtc_state->stream->output_color_space;
> +
> +               dc_stream_release(new_stream);
> +       }
> +}
> +
>  /**
>   * amdgpu_dm_atomic_commit_tail() - AMDgpu DM's commit tail implementation.
>   * @state: The atomic state to commit
> @@ -7508,7 +7706,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>                 struct dc_stream_update stream_update;
>                 struct dc_info_packet hdr_packet;
>                 struct dc_stream_status *status = NULL;
> -               bool abm_changed, hdr_changed, scaling_changed;
> +               bool abm_changed, hdr_changed, scaling_changed, pixenc_changed;
>
>                 memset(&dummy_updates, 0, sizeof(dummy_updates));
>                 memset(&stream_update, 0, sizeof(stream_update));
> @@ -7534,7 +7732,10 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>                 hdr_changed =
>                         is_hdr_metadata_different(old_con_state, new_con_state);
>
> -               if (!scaling_changed && !abm_changed && !hdr_changed)
> +               pixenc_changed = dm_new_con_state->pixel_encoding !=
> +                                dm_old_con_state->pixel_encoding;
> +
> +               if (!scaling_changed && !abm_changed && !hdr_changed && !pixenc_changed)
>                         continue;
>
>                 stream_update.stream = dm_new_crtc_state->stream;
> @@ -7557,6 +7758,13 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>                         stream_update.hdr_static_metadata = &hdr_packet;
>                 }
>
> +               if (pixenc_changed) {
> +                       update_stream_for_pixel_encoding(&stream_update,
> +                               connector,
> +                               dm_old_crtc_state, dm_new_crtc_state,
> +                               dm_new_con_state);
> +               }
> +
>                 status = dc_stream_get_status(dm_new_crtc_state->stream);
>                 WARN_ON(!status);
>                 WARN_ON(!status->plane_count);
> @@ -7911,7 +8119,6 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm,
>                                                              &new_crtc_state->mode,
>                                                              dm_new_conn_state,
>                                                              dm_old_crtc_state->stream);
> -
>                 /*
>                  * we can have no stream on ACTION_SET if a display
>                  * was disconnected during S3, in this case it is not an
> @@ -8578,6 +8785,12 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
>                 if (dm_old_con_state->abm_level !=
>                     dm_new_con_state->abm_level)
>                         new_crtc_state->connectors_changed = true;
> +
> +               if (dm_old_con_state->pixel_encoding !=
> +                   dm_new_con_state->pixel_encoding) {
> +                       new_crtc_state->connectors_changed = true;
> +                       new_crtc_state->mode_changed = true;
> +               }
>         }
>
>  #if defined(CONFIG_DRM_AMD_DC_DCN)
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> index dd1559c743c2..e46bdd279d0f 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -450,6 +450,7 @@ struct dm_connector_state {
>         uint8_t abm_level;
>         int vcpi_slots;
>         uint64_t pbn;
> +       enum dc_pixel_encoding pixel_encoding;
>  };
>
>  #define to_dm_connector_state(x)\
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
> index 92eb1ca1634f..24743ee9d9da 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
> @@ -1881,6 +1881,11 @@ static enum surface_update_type check_update_surfaces_for_stream(
>
>                 if (stream_update->output_csc_transform || stream_update->output_color_space)
>                         su_flags->bits.out_csc = 1;
> +
> +               if (stream_update->timing_for_pixel_encoding) {
> +                       su_flags->bits.pixel_encoding = 1;
> +                       elevate_update_type(&overall_type, UPDATE_TYPE_FULL);
> +               }
>         }
>
>         for (i = 0 ; i < surface_count; i++) {
> @@ -2183,6 +2188,10 @@ static void copy_stream_update_to_stream(struct dc *dc,
>                         update->dsc_config = NULL;
>                 }
>         }
> +
> +       if (update->timing_for_pixel_encoding) {
> +               stream->timing = *update->timing_for_pixel_encoding;
> +       }
>  }
>
>  static void commit_planes_do_stream_update(struct dc *dc,
> @@ -2211,7 +2220,8 @@ static void commit_planes_do_stream_update(struct dc *dc,
>                         if ((stream_update->hdr_static_metadata && !stream->use_dynamic_meta) ||
>                                         stream_update->vrr_infopacket ||
>                                         stream_update->vsc_infopacket ||
> -                                       stream_update->vsp_infopacket) {
> +                                       stream_update->vsp_infopacket ||
> +                                       stream_update->timing_for_pixel_encoding) {
>                                 resource_build_info_frame(pipe_ctx);
>                                 dc->hwss.update_info_frame(pipe_ctx);
>                         }
> diff --git a/drivers/gpu/drm/amd/display/dc/dc_stream.h b/drivers/gpu/drm/amd/display/dc/dc_stream.h
> index d9888f316da6..0e1ef24d8855 100644
> --- a/drivers/gpu/drm/amd/display/dc/dc_stream.h
> +++ b/drivers/gpu/drm/amd/display/dc/dc_stream.h
> @@ -126,6 +126,7 @@ union stream_update_flags {
>                 uint32_t gamut_remap:1;
>                 uint32_t wb_update:1;
>                 uint32_t dsc_changed : 1;
> +               uint32_t pixel_encoding:1;
>         } bits;
>
>         uint32_t raw;
> @@ -262,6 +263,7 @@ struct dc_stream_update {
>
>         struct dc_writeback_update *wb_update;
>         struct dc_dsc_config *dsc_config;
> +       struct dc_crtc_timing *timing_for_pixel_encoding;
>  #if defined(CONFIG_DRM_AMD_DC_DCN3_0)
>         struct dc_transfer_func *func_shaper;
>         struct dc_3dlut *lut3d_func;
> --
> 2.26.2
>
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On 22/09/2020 21:33, Alex Deucher wrote:
>> +/**
>> + * DOC: pixel_encoding (string)
>> + * Specify the initial pixel encoding used by a connector.
>> + */
>> +static char amdgpu_pixel_encoding[MAX_INPUT];
>> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
>> +module_param_string(pixel_encoding, amdgpu_pixel_encoding, sizeof(amdgpu_pixel_encoding), 0444);
> 
> You can drop this part.  We don't need a module parameter if we have a
> kms property.
> 
> Alex

OK, but is there then an alternative means of setting the pixel encoding to be used immediately on boot or when amdgpu loads? Also are there user tools other than xrandr to change a KMS property, for Wayland and console users? 

-James

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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Alex Deucher]

On Tue, Sep 22, 2020 at 4:51 PM James Ettle <james@ettle.org.uk> wrote:
>
> On 22/09/2020 21:33, Alex Deucher wrote:
> >> +/**
> >> + * DOC: pixel_encoding (string)
> >> + * Specify the initial pixel encoding used by a connector.
> >> + */
> >> +static char amdgpu_pixel_encoding[MAX_INPUT];
> >> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
> >> +module_param_string(pixel_encoding, amdgpu_pixel_encoding, sizeof(amdgpu_pixel_encoding), 0444);
> >
> > You can drop this part.  We don't need a module parameter if we have a
> > kms property.
> >
> > Alex
>
> OK, but is there then an alternative means of setting the pixel encoding to be used immediately on boot or when amdgpu loads? Also are there user tools other than xrandr to change a KMS property, for Wayland and console users?

You can force some things on the kernel command line, but I don't
recall whether that includes kms properties or not.  As for ways to
change properties, the KMS API provides a way.  those are exposed via
randr when using X.  When using wayland compositors, it depends on the
compositor.

Alex
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Harry Wentland]

On 2020-09-25 5:18 p.m., Alex Deucher wrote:
> On Tue, Sep 22, 2020 at 4:51 PM James Ettle <james@ettle.org.uk> wrote:
>>
>> On 22/09/2020 21:33, Alex Deucher wrote:
>>>> +/**
>>>> + * DOC: pixel_encoding (string)
>>>> + * Specify the initial pixel encoding used by a connector.
>>>> + */
>>>> +static char amdgpu_pixel_encoding[MAX_INPUT];
>>>> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
>>>> +module_param_string(pixel_encoding, amdgpu_pixel_encoding, sizeof(amdgpu_pixel_encoding), 0444);
>>>
>>> You can drop this part.  We don't need a module parameter if we have a
>>> kms property.
>>>
>>> Alex
>>
>> OK, but is there then an alternative means of setting the pixel encoding to be used immediately on boot or when amdgpu loads? Also are there user tools other than xrandr to change a KMS property, for Wayland and console users?
> 
> You can force some things on the kernel command line, but I don't
> recall whether that includes kms properties or not.  As for ways to
> change properties, the KMS API provides a way.  those are exposed via
> randr when using X.  When using wayland compositors, it depends on the
> compositor.
> 

I'm not aware of a way to specify KMS properties through the kernel
command line. I don't think it's possible.

For atomic userspace the userspace wants to be the authority on the KMS
config. I'm not sure there's a way to set these properties with Wayland
unless a Wayland compositor plumbs them through.

Can you summarize on a higher level what problem you're trying to solve?
I wonder if it'd be better solved with properties on a DRM level that
all drivers can follow if desired.

Harry

> Alex
> 
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On Mon, 2020-09-28 at 10:26 -0400, Harry Wentland wrote:
> 
> On 2020-09-25 5:18 p.m., Alex Deucher wrote:
> > On Tue, Sep 22, 2020 at 4:51 PM James Ettle <james@ettle.org.uk>
> > wrote:
> > > On 22/09/2020 21:33, Alex Deucher wrote:
> > > > > +/**
> > > > > + * DOC: pixel_encoding (string)
> > > > > + * Specify the initial pixel encoding used by a connector.
> > > > > + */
> > > > > +static char amdgpu_pixel_encoding[MAX_INPUT];
> > > > > +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
> > > > > +module_param_string(pixel_encoding, amdgpu_pixel_encoding,
> > > > > sizeof(amdgpu_pixel_encoding), 0444);
> > > > 
> > > > You can drop this part.  We don't need a module parameter if we
> > > > have a
> > > > kms property.
> > > > 
> > > > Alex
> > > 
> > > OK, but is there then an alternative means of setting the pixel
> > > encoding to be used immediately on boot or when amdgpu loads?
> > > Also are there user tools other than xrandr to change a KMS
> > > property, for Wayland and console users?
> > 
> > You can force some things on the kernel command line, but I don't
> > recall whether that includes kms properties or not.  As for ways to
> > change properties, the KMS API provides a way.  those are exposed
> > via
> > randr when using X.  When using wayland compositors, it depends on
> > the
> > compositor.
> > 
> 
> I'm not aware of a way to specify KMS properties through the kernel
> command line. I don't think it's possible.
> 
> For atomic userspace the userspace wants to be the authority on the
> KMS
> config. I'm not sure there's a way to set these properties with
> Wayland
> unless a Wayland compositor plumbs them through.
> 
> Can you summarize on a higher level what problem you're trying to
> solve?
> I wonder if it'd be better solved with properties on a DRM level that
> all drivers can follow if desired.
> 
> Harry
> 
> > Alex
> > 

The problem this is trying to solve is that the pixel format defaults
to YCbCr444 on HDMI if the monitor claims to support it, in preference
to RGB. This behaviour is hard-coded (see the
comment fill_stream_properties_from_drm_display_mode) and there is no
way for the user to change the pixel format to RGB, other than hacking
the EDID to disable the YCbCr flags.

Using YCbCr (rather than RGB) has been reported to cause suboptimal
results for some users: colour quality issues or perceptible conversion
latency at the monitor end -- see:

https://gitlab.freedesktop.org/drm/amd/-/issues/476

for the full details.

This patch tries to solve this issue by adding a DRM property so Xorg
users can change the pixel encoding on-the-fly, and a module parameter
to set the default encoding at amdgpu's init for all users.

[I suppose an alternative here is to look into the rationale of
defaulting to YCbCr444 on HDMI when the monitor also supports RGB. For
reference although on my kit I see no detrimental effects from YCbCr,
I'm using onboard graphics with a motherboard that has just D-sub and
HDMI -- so DisplayPort's not an option.]

-James


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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Christian König]

Am 28.09.20 um 19:35 schrieb James Ettle:
> On Mon, 2020-09-28 at 10:26 -0400, Harry Wentland wrote:
>> On 2020-09-25 5:18 p.m., Alex Deucher wrote:
>>> On Tue, Sep 22, 2020 at 4:51 PM James Ettle <james@ettle.org.uk>
>>> wrote:
>>>> On 22/09/2020 21:33, Alex Deucher wrote:
>>>>>> +/**
>>>>>> + * DOC: pixel_encoding (string)
>>>>>> + * Specify the initial pixel encoding used by a connector.
>>>>>> + */
>>>>>> +static char amdgpu_pixel_encoding[MAX_INPUT];
>>>>>> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
>>>>>> +module_param_string(pixel_encoding, amdgpu_pixel_encoding,
>>>>>> sizeof(amdgpu_pixel_encoding), 0444);
>>>>> You can drop this part.  We don't need a module parameter if we
>>>>> have a
>>>>> kms property.
>>>>>
>>>>> Alex
>>>> OK, but is there then an alternative means of setting the pixel
>>>> encoding to be used immediately on boot or when amdgpu loads?
>>>> Also are there user tools other than xrandr to change a KMS
>>>> property, for Wayland and console users?
>>> You can force some things on the kernel command line, but I don't
>>> recall whether that includes kms properties or not.  As for ways to
>>> change properties, the KMS API provides a way.  those are exposed
>>> via
>>> randr when using X.  When using wayland compositors, it depends on
>>> the
>>> compositor.
>>>
>> I'm not aware of a way to specify KMS properties through the kernel
>> command line. I don't think it's possible.
>>
>> For atomic userspace the userspace wants to be the authority on the
>> KMS
>> config. I'm not sure there's a way to set these properties with
>> Wayland
>> unless a Wayland compositor plumbs them through.
>>
>> Can you summarize on a higher level what problem you're trying to
>> solve?
>> I wonder if it'd be better solved with properties on a DRM level that
>> all drivers can follow if desired.
>>
>> Harry
>>
>>> Alex
>>>
> The problem this is trying to solve is that the pixel format defaults
> to YCbCr444 on HDMI if the monitor claims to support it, in preference
> to RGB. This behaviour is hard-coded (see the
> comment fill_stream_properties_from_drm_display_mode) and there is no
> way for the user to change the pixel format to RGB, other than hacking
> the EDID to disable the YCbCr flags.
>
> Using YCbCr (rather than RGB) has been reported to cause suboptimal
> results for some users: colour quality issues or perceptible conversion
> latency at the monitor end -- see:
>
> https://gitlab.freedesktop.org/drm/amd/-/issues/476
>
> for the full details.
>
> This patch tries to solve this issue by adding a DRM property so Xorg
> users can change the pixel encoding on-the-fly, and a module parameter
> to set the default encoding at amdgpu's init for all users.
>
> [I suppose an alternative here is to look into the rationale of
> defaulting to YCbCr444 on HDMI when the monitor also supports RGB. For
> reference although on my kit I see no detrimental effects from YCbCr,
> I'm using onboard graphics with a motherboard that has just D-sub and
> HDMI -- so DisplayPort's not an option.]

Ah, that problem again. Yes, that's an issue since the early fglrx days 
on linux.

Shouldn't the pixel encoding be part of the mode to run ?

Regards,
Christian.

>
> -James
>
>
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Kazlauskas, Nicholas]

On 2020-09-28 3:31 p.m., Christian König wrote:
> Am 28.09.20 um 19:35 schrieb James Ettle:
>> On Mon, 2020-09-28 at 10:26 -0400, Harry Wentland wrote:
>>> On 2020-09-25 5:18 p.m., Alex Deucher wrote:
>>>> On Tue, Sep 22, 2020 at 4:51 PM James Ettle <james@ettle.org.uk>
>>>> wrote:
>>>>> On 22/09/2020 21:33, Alex Deucher wrote:
>>>>>>> +/**
>>>>>>> + * DOC: pixel_encoding (string)
>>>>>>> + * Specify the initial pixel encoding used by a connector.
>>>>>>> + */
>>>>>>> +static char amdgpu_pixel_encoding[MAX_INPUT];
>>>>>>> +MODULE_PARM_DESC(pixel_encoding, "Override pixel encoding");
>>>>>>> +module_param_string(pixel_encoding, amdgpu_pixel_encoding,
>>>>>>> sizeof(amdgpu_pixel_encoding), 0444);
>>>>>> You can drop this part.  We don't need a module parameter if we
>>>>>> have a
>>>>>> kms property.
>>>>>>
>>>>>> Alex
>>>>> OK, but is there then an alternative means of setting the pixel
>>>>> encoding to be used immediately on boot or when amdgpu loads?
>>>>> Also are there user tools other than xrandr to change a KMS
>>>>> property, for Wayland and console users?
>>>> You can force some things on the kernel command line, but I don't
>>>> recall whether that includes kms properties or not.  As for ways to
>>>> change properties, the KMS API provides a way.  those are exposed
>>>> via
>>>> randr when using X.  When using wayland compositors, it depends on
>>>> the
>>>> compositor.
>>>>
>>> I'm not aware of a way to specify KMS properties through the kernel
>>> command line. I don't think it's possible.
>>>
>>> For atomic userspace the userspace wants to be the authority on the
>>> KMS
>>> config. I'm not sure there's a way to set these properties with
>>> Wayland
>>> unless a Wayland compositor plumbs them through.
>>>
>>> Can you summarize on a higher level what problem you're trying to
>>> solve?
>>> I wonder if it'd be better solved with properties on a DRM level that
>>> all drivers can follow if desired.
>>>
>>> Harry
>>>
>>>> Alex
>>>>
>> The problem this is trying to solve is that the pixel format defaults
>> to YCbCr444 on HDMI if the monitor claims to support it, in preference
>> to RGB. This behaviour is hard-coded (see the
>> comment fill_stream_properties_from_drm_display_mode) and there is no
>> way for the user to change the pixel format to RGB, other than hacking
>> the EDID to disable the YCbCr flags.
>>
>> Using YCbCr (rather than RGB) has been reported to cause suboptimal
>> results for some users: colour quality issues or perceptible conversion
>> latency at the monitor end -- see:
>>
>> https://gitlab.freedesktop.org/drm/amd/-/issues/476 
>>
>>
>> for the full details.
>>
>> This patch tries to solve this issue by adding a DRM property so Xorg
>> users can change the pixel encoding on-the-fly, and a module parameter
>> to set the default encoding at amdgpu's init for all users.
>>
>> [I suppose an alternative here is to look into the rationale of
>> defaulting to YCbCr444 on HDMI when the monitor also supports RGB. For
>> reference although on my kit I see no detrimental effects from YCbCr,
>> I'm using onboard graphics with a motherboard that has just D-sub and
>> HDMI -- so DisplayPort's not an option.]
> 
> Ah, that problem again. Yes, that's an issue since the early fglrx days 
> on linux.
> 
> Shouldn't the pixel encoding be part of the mode to run ?
> 
> Regards,
> Christian.

DRM modes don't specify the encoding. The property as part of this patch 
lets userspace override it but the userspace GUI support isn't there on 
Wayland IIRC.

I'm fine with adding the properties but I don't think the module 
parameter is the right solution here. I think it's better if we try to 
get this into atomic userspace as well or revive efforts that have been 
already started before.

The problem with the module parameters is that it'd be applying a 
default to every DRM connector. No way to specify different defaults per 
DRM connector, nor do we know the full connector set at driver 
initialization. The list is dynamic and can change when you plug/unplug 
MST displays.

Regards,
Nicholas Kazlauskas

> 
>>
>> -James
>>
>>
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>>
> 

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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On Mon, 2020-09-28 at 16:12 -0400, Kazlauskas, Nicholas wrote:
> 
> The problem with the module parameters is that it'd be applying a 
> default to every DRM connector. No way to specify different defaults
> per 
> DRM connector, nor do we know the full connector set at driver 
> initialization. The list is dynamic and can change when you
> plug/unplug 
> MST displays.

I just want to point out that the module parameter does support
connector-specific values, e.g.

  amdgpu.pixel_encoding=HDMI-A-1:rgb

should only affect the connector named HDMI-A-1 (unless I've coded it
wrong -- I don't have enough video ports to test it thoroughly). If
there's no such-named connector the parameter should be ignored. In
contrast with no named connector given, e.g.

  amdgpu.pixel_encoding=rgb

should match any connector. Multiple connectors can be given comma-
separated. I admit the solution here is crude -- it just stores the
string and rescans it when required.

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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[Alex Deucher]

On Mon, Sep 28, 2020 at 4:24 PM James Ettle <james@ettle.org.uk> wrote:
>
> On Mon, 2020-09-28 at 16:12 -0400, Kazlauskas, Nicholas wrote:
> >
> > The problem with the module parameters is that it'd be applying a
> > default to every DRM connector. No way to specify different defaults
> > per
> > DRM connector, nor do we know the full connector set at driver
> > initialization. The list is dynamic and can change when you
> > plug/unplug
> > MST displays.
>
> I just want to point out that the module parameter does support
> connector-specific values, e.g.
>
>   amdgpu.pixel_encoding=HDMI-A-1:rgb
>
> should only affect the connector named HDMI-A-1 (unless I've coded it
> wrong -- I don't have enough video ports to test it thoroughly). If
> there's no such-named connector the parameter should be ignored. In
> contrast with no named connector given, e.g.
>
>   amdgpu.pixel_encoding=rgb
>
> should match any connector. Multiple connectors can be given comma-
> separated. I admit the solution here is crude -- it just stores the
> string and rescans it when required.

Yes, but module parameters global for all devices claimed by that
driver.  E.g., if you have a system with 2 or 3 AMD GPUs in it, that
will be applied to all of them.  I think if we want to be able to set
KMS properties on the kernel command line, we should add the
functionality to the drm core so it works for all drivers and
properties.  We already have this for basic modesetting.

Alex
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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On Mon, 2020-09-28 at 16:32 -0400, Alex Deucher wrote:
> Yes, but module parameters global for all devices claimed by that
> driver.  E.g., if you have a system with 2 or 3 AMD GPUs in it, that
> will be applied to all of them.  I think if we want to be able to set
> KMS properties on the kernel command line, we should add the
> functionality to the drm core so it works for all drivers and
> properties.  We already have this for basic modesetting.
> 
> Alex

Thanks for clarifying that -- I see what was meant now.

Personally I'm not wedded to the module parameter, but I think if this
is to be of use to those who are experiencing problems it does need
*some* way of specifying the encoding pretty early on (for things like
boot splashes and GDM -- which I believe is on Wayland).

-James


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Re: [PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On 28/09/2020 21:12, Kazlauskas, Nicholas wrote:
> 
> DRM modes don't specify the encoding. The property as part of this patch 
> lets userspace override it but the userspace GUI support isn't there on 
> Wayland IIRC.
> 
> I'm fine with adding the properties but I don't think the module 
> parameter is the right solution here. I think it's better if we try to 
> get this into atomic userspace as well or revive efforts that have been 
> already started before.
> 
> The problem with the module parameters is that it'd be applying a 
> default to every DRM connector. No way to specify different defaults per 
> DRM connector, nor do we know the full connector set at driver 
> initialization. The list is dynamic and can change when you plug/unplug 
> MST displays.
> 
What about using the existing "video=" kernel command-line option? I 
looks like this acts at the DRM level and is a driver-neutral mechanism 
for specifying defaults on a per-connector basis.

It also has a straightforward means for parsing additional arbitrary 
options that could be used -- from what I can make out this would 
require adding pixel encoding to struct drm_cmdline_mode.

Regards,

-James
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