sdk/banjo/fuchsia.hardware.display.controller/display-controller.fidl - fuchsia - Git at Google

 // Copyright 2018 The Fuchsia Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 library fuchsia.hardware.display.controller;

 using fuchsia.hardware.audiotypes;
 using zx;

 alias ZxPixelFormat = uint32;

 alias ZxUnownedHandle = uint32;

 type ImageType = strict enum : uint32 {
     /// The image is linear and VMO backed.
     SIMPLE = 0;

     // Intentionally left some gap between SIMPLE and CAPTURE.

     /// The image is used for capture
     CAPTURE = 10;
 };

 /// A structure containing information about an image.
 type Image = struct {
     /// The width and height of the image in pixels.
     width uint32;
     height uint32;

     /// The pixel format of the image.
     pixel_format ZxPixelFormat;

     /// The type conveys information about what is providing the pixel data. If this is not
     /// IMAGE_TYPE_SIMPLE, it is up to the driver and buffer producer to agree on the meaning
     /// of the value through some mechanism outside the scope of this API.
     type uint32;

     /// A driver-defined handle to the image. Each handle must be unique.
     handle uint64;
 };

 const INVALID_DISPLAY_ID uint32 = 0;
 const INVALID_ID uint32 = 0;
 const INVALID_CONFIG_STAMP_VALUE uint64 = 0;

 /// A unique stamp representing a unique set of display configuration
 /// in ApplyConfiguration().
 type ConfigStamp = struct {
     /// For valid configurations, the value should not be equal to
     /// `INVALID_CONFIG_STAMP_VALUE`.
     value uint64;
 };

 /// A fallback structure to convey display information without an edid.
 type DisplayParams = struct {
     width uint32;
     height uint32;
     refresh_rate_e2 uint32;
 };

 /// Info about valid cursor configurations.
 type CursorInfo = struct {
     /// The width and height of the cursor configuration, in pixels.
     width uint32;
     height uint32;
     format ZxPixelFormat;
 };

 type Panel = strict union {
     /// The bus_id to use to read this display's edid from the device's i2c protocol.
     1: i2c_bus_id uint32;
     /// The display's parameters if an edid is not present.
     2: params DisplayParams;
 };

 /// A structure containing information a connected display.
 type AddedDisplayArgs = struct {
     display_id uint64;

     /// A flag indicating whether or not the display has a valid edid.
     ///
     /// If true, the device should expose an ZX_PROTOCOL_I2C_IMPL device through get_protocol, in
     /// addition to the ZX_PROTOCOL_DISPLAY_CONTROLLER_IMPL protocol. Note that the i2c device
     /// will be called from the on_displays_changed callback, so care should be taken to avoid
     /// deadlocks or double-locking.
     ///
     /// If no edid is present, then the meaning of display_config's mode structure is
     /// undefined, and drivers should ignore it in check_configuration and apply_configuration.
     edid_present bool;
     panel Panel;

     /// A list of pixel formats supported by the display. The first entry is the
     /// preferred pixel format.
     pixel_format vector<ZxPixelFormat>:MAX;

     /// A list of cursor configurations most likely to be accepted by the driver. Can
     /// be null if cursor_count is 0.
     ///
     /// The driver may reject some of these configurations in some circumstances, and
     /// it may accept other configurations, but at least one of these configurations
     /// should be valid at most times.
     cursor_info vector<CursorInfo>:MAX;
 };

 /// Out parameters will be populated before on_displays_changed returns.
 type AddedDisplayInfo = struct {
     is_hdmi_out bool;
     is_standard_srgb_out bool;

     audio_format_count uint32;

     /// All strings are null-terminated. |manufacturer_id| is guaranteed to have
     /// length 3, all other strings may be empty.
     manufacturer_id string:4;
     /// non-null
     manufacturer_name string:MAX;
     /// null-terminated
     monitor_name string:14;
     /// null-terminated
     monitor_serial string:14;

     // physical horizontal size in millimeters
     horizontal_size_mm uint32;
     // physical vertical size in millimeters
     vertical_size_mm uint32;
 };

 /// The client will not make any `ZX_PROTOCOL_DISPLAY_CONTROLLER_IMPL` calls into the device
 /// during these callbacks.
 @transport("Banjo")
 @banjo_layout("ddk-interface")
 protocol DisplayControllerInterface {
     /// Callbacks which are invoked when displays are added or removed. |added_display_list| and
     /// |removed_display_list| point to arrays of the display ids which were added and removed. If
     /// |added_display_count| or |removed_display_count| is 0, the corresponding array can be NULL.
     ///
     /// The driver must be done accessing any images which were on the removed displays.
     ///
     /// The driver should call this function when the callback is registered if any displays
     /// are present.
     OnDisplaysChanged(struct {
         added_display vector<AddedDisplayArgs>:MAX;
         removed_display vector<uint64>:MAX;
     }) -> (struct {
         display_info vector<AddedDisplayInfo>:MAX;
     });

     /// Events which are invoked when display vsync occurs.
     ///
     /// Arguments
     /// - |timestamp|
     ///      The ZX_CLOCK_MONOTONIC timestamp at which the vsync occurred.
     /// - |config_stamp|
     ///      The config stamp of the latest configuration that is currently
     ///      fully applied to all the layers of the display with `display_id`.
     ///        If none of the configurations are currently fully applied to
     ///      this display, a null value will be passed to the driver.
     ///        Note that an `ApplyConfiguration()` call may contain multiple
     ///      configurations with a certain `config_stamp`; Only the application
     ///      status of the configuration with ID `display_id` is related.
     ///
     /// The driver must call this function for all vsync events, even if the
     /// display has no images displayed.
     OnDisplayVsync(struct {
         display_id uint64;
         timestamp zx.time;
         config_stamp box<ConfigStamp>;
     }) -> ();

     GetAudioFormat(struct {
         display_id uint64;
         fmt_idx uint32;
     }) -> (struct {
         s zx.status;
         fmt fuchsia.hardware.audiotypes.AudioTypesAudioStreamFormatRange;
     });
 };

 type Alpha = strict enum : uint8 {
     DISABLE = 0;
     PREMULTIPLIED = 1;
     HW_MULTIPLY = 2;
 };

 /// Rotations are applied counter-clockwise, and are applied before reflections.
 type FrameTransform = strict enum : uint32 {
     IDENTITY = 0;
     REFLECT_X = 1;
     REFLECT_Y = 2;
     ROT_90 = 3;
     ROT_180 = 4;
     ROT_270 = 5;
     ROT_90_REFLECT_X = 6;
     ROT_90_REFLECT_Y = 7;
 };

 type Frame = struct {
     /// (|x_pos|, |y_pos|) specifies the position of the upper-left corner
     /// of the frame.
     x_pos uint32;
     y_pos uint32;
     width uint32;
     height uint32;
 };

 type PrimaryLayer = struct {
     image Image;

     /// An ALPHA_* constant.
     ///
     /// If |alpha_mode| == `ALPHA_DISABLED`, the layer is opaque and alpha_layer_val is ignored.
     ///
     /// If |alpha_mode| == `PREMULTIPLIED` or `HW_MULTIPLY` and |alpha_layer_val| is NaN, the alpha
     /// used when blending is determined by the per-pixel alpha channel.
     ///
     /// If |alpha_mode| == `PREMULTIPLIED` or `HW_MULTIPLY` and |alpha_layer_val| is not NaN, the
     /// alpha used when blending is the product of alpha_layer_val and any per-pixel alpha.
     /// Additionally, if alpha_mode == PREMULTIPLIED, then the hardware must premultiply the color
     /// channel with alpha_layer_val before blending.
     ///
     /// If alpha_layer_val is not NaN, it will be in the range [0, 1].
     alpha_mode Alpha;
     alpha_layer_val float32;

     transform_mode FrameTransform;

     /// The source frame, where (0,0) is the top-left corner of the image. The
     /// client guarantees that src_frame lies entirely within the image.
     src_frame Frame;

     /// The destination frame, where (0,0) is the top-left corner of the
     /// composed output. The client guarantees that dest_frame lies entirely
     /// within the composed output.
     dest_frame Frame;
 };

 type CursorLayer = struct {
     image Image;

     /// The position of the top-left corner of the cursor's image. When being
     /// applied to a display, the cursor is guaranteed to have at least one
     /// pixel of overlap with the display.
     x_pos int32;
     y_pos int32;
 };

 type ColorLayer = struct {
     format ZxPixelFormat;
     /// The color to use for the layer. The color is little-endian, and is
     /// guaranteed to be of the appropriate size.
     color vector<uint8>:MAX;
 };

 /// Types of layers.
 type LayerType = strict enum : uint32 {
     PRIMARY = 0;
     CURSOR = 1;
     COLOR = 2;
 };

 type LayerConfig = strict union {
     1: primary PrimaryLayer;
     2: cursor CursorLayer;
     3: color ColorLayer;
 };

 type Layer = struct {
     type LayerType;
     /// z_index of the layer. See |check_configuration| and |apply_configuration|.
     z_index uint32;
     cfg LayerConfig;
 };

 /// constants for display_config's mode_flags field
 type ModeFlag = strict enum : uint32 {
     VSYNC_POSITIVE = 0x1;
     HSYNC_POSITIVE = 0x2;
     INTERLACED = 0x4;
     ALTERNATING_VBLANK = 0x8;
     DOUBLE_CLOCKED = 0x10;
 };

 /// The video parameters which specify the display mode.
 type DisplayMode = struct {
     pixel_clock_10khz uint32;
     h_addressable uint32;
     h_front_porch uint32;
     h_sync_pulse uint32;
     h_blanking uint32;
     v_addressable uint32;
     v_front_porch uint32;
     v_sync_pulse uint32;
     v_blanking uint32;
     /// A bitmask of MODE_FLAG_* values
     flags uint32;
 };

 type ColorConversion = strict enum : uint32 {
     /// If set, use the 0 vector for the color conversion preoffset
     PREOFFSET = 0x1;
     /// If set, use the identity matrix for the color conversion coefficients
     COEFFICIENTS = 0x2;
     /// If set, use the 0 vector for the color conversion postoffset
     POSTOFFSET = 0x4;
 };

 type DisplayConfig = struct {
     /// the display id to which the configuration applies
     display_id uint64;

     mode DisplayMode;

     /// Bitmask of COLOR_CONVERSION_* flags
     cc_flags uint32;
     /// Color conversion is applied to each pixel according to the formula:
     ///
     /// (cc_coefficients * (pixel + cc_preoffsets)) + cc_postoffsets
     ///
     /// where pixel is a column vector consisting of the pixel's 3 components.
     cc_preoffsets array<float32, 3>;
     cc_coefficients array<array<float32, 3>, 3>;
     cc_postoffsets array<float32, 3>;

     @mutable
     @out_of_line_contents
     layer vector<Layer>:MAX;

     /// Flag to indicate valid gamma table
     gamma_table_present bool;
     /// Flag to indicate whether display driver should re-apply gamma correction table to hardware
     apply_gamma_table bool;
     /// Gamma Table (Red, Green and Blue)
     @mutable
     gamma_red vector<float32>:MAX;
     @mutable
     gamma_green vector<float32>:MAX;
     @mutable
     gamma_blue vector<float32>:MAX;
 };

 type ConfigDisplay = strict enum : uint32 {
     /// The display mode configuration is valid. Note that this is distinct from
     /// whether or not the layer configuration is valid.
     OK = 0;
     /// Error indicating that the hardware cannot simultaneously support the
     /// requested number of displays.
     TOO_MANY = 1;
     /// Error indicating that the hardware cannot simultaneously support the given
     /// set of display modes. To support a mode, the display must be able to display
     /// a single layer with width and height equal to the requested mode and the
     /// preferred pixel format.
     UNSUPPORTED_MODES = 2;
 };

 type Client = strict enum : uint32 {
     /// The client should convert the corresponding layer to a primary layer.
     USE_PRIMARY = 0x1;
     /// The client should compose all layers with MERGE_BASE and MERGE_SRC into a new,
     /// single primary layer at the MERGE_BASE layer's z-order. The driver must accept
     /// a fullscreen layer with the default pixel format, but may accept other layer
     /// parameters.
     ///
     /// MERGE_BASE should only be set on one layer per display. If it is set on multiple
     /// layers, the client will arbitrarily pick one and change the rest to MERGE_SRC.
     MERGE_BASE = 0x2;
     MERGE_SRC = 0x4;
     /// The client should pre-scale the image so that src_frame's dimensions are equal
     /// to dest_frame's dimensions.
     FRAME_SCALE = 0x8;
     /// The client should pre-clip the image so that src_frame's dimensions are equal to
     /// the image's dimensions.
     SRC_FRAME = 0x10;
     /// The client should pre-apply the transformation so TRANSFORM_IDENTITY can be used.
     TRANSFORM = 0x20;
     /// The client should apply the color conversion.
     COLOR_CONVERSION = 0x40;
     /// The client should apply the alpha transformation itself.
     ALPHA = 0x80;
     /// The client cannot control the display gamma, and must accept
     /// the uncalibrated output. Clients are expected to produce linear
     /// buffers, and as such they cannot perform software gamma
     /// correction.
     GAMMA = 0x100;
 };

 /// The client guarantees that check_configuration and apply_configuration are always
 /// made from a single thread. The client makes no other threading guarantees.
 @transport("Banjo")
 @banjo_layout("ddk-protocol")
 protocol DisplayControllerImpl {
     /// The function will only be called once, and it will be called before any other
     /// functions are called.
     SetDisplayControllerInterface(resource struct {
         intf client_end:DisplayControllerInterface;
     }) -> ();

     /// Imports an image from a buffer collection into the driver. The driver should set
     /// image->handle.
     ImportImage(struct {
         @in_out
         image Image;
         collection ZxUnownedHandle;
         index uint32;
     }) -> (struct {
         s zx.status;
     });

     /// Releases any driver state associated with the given image. The client guarantees that
     /// any images passed to apply_config will not be released until a vsync occurs with a
     /// more recent image.
     ReleaseImage(struct {
         @in_out
         image Image;
     }) -> ();

     /// Validates the given configuration.
     ///
     /// The configuration may not include all displays. Omitted displays should be treated as
     /// whichever of off or displaying a blank screen results in a more permissive validation.
     ///
     /// All displays in a configuration will have at least one layer. The layers will be
     /// arranged in increasing z-order, and their z_index fields will be set consecutively.
     ///
     /// Whether or not the driver can accept the configuration cannot depend on the
     /// particular image handles, as it must always be possible to present a new image in
     /// place of another image with a matching configuration. It also cannot depend on the
     /// cursor position, as that can be updated without another call to check_configuration.
     ///
     /// display_cfg_result should be set to a CONFIG_DISPLAY_* error if the combination of
     /// display modes is not supported.
     ///
     /// layer_cfg_result points to an array of arrays. The primary length is display_count, the
     /// secondary lengths are the corresponding display_cfg's layer_count. If display_cfg_result
     /// is CONFIG_DISPLAY_OK, any errors in layer configuration should be returned as a CLIENT*
     /// flag in the corresponding layer_cfg_result entry.
     ///
     /// The driver must not retain references to the configuration after this function returns.
     /// TODO: Fix me...
     CheckConfiguration(struct {
         @inner_pointer
         display_config vector<DisplayConfig>:MAX;
     }) -> (struct {
         display_cfg_result uint32;
         @callee_allocated
         layer_cfg_result vector<uint32>:MAX;
     });

     /// Applies the configuration.
     ///
     /// All configurations passed to this function will be derived from configurations which
     /// have been successfully validated, with the only differences either being omitted layers
     /// or different image handles. To account for any layers which are not present, the driver
     /// must use the z_index values of the present layers to configure them as if the whole
     /// configuration was present.
     ///
     /// Unlike with check_configuration, displays included in the configuration are not
     /// guaranteed to include any layers. Both omitted displays and displays with no layers
     /// can either be turned off or set to display a blank screen, but for displays with no
     /// layers there is a strong preference to display a blank screen instead of turn them off.
     /// In either case, the driver must drop all references to old images and invoke the vsync
     /// callback after doing so.
     ///
     /// `config_stamp` is a non-zero unique stamp to identify each configuration.
     /// Callers must guarantee that `config_stamp` is unique for each `ApplyConfiguration()`
     /// call.
     ///
     /// The driver must not retain references to the configuration after this function returns.
     ApplyConfiguration(struct {
         @inner_pointer
         display_config vector<DisplayConfig>:MAX;
         config_stamp ConfigStamp;
     }) -> ();

     /// Set ELD for one display.
     ///
     /// This method is called independently from the CheckConfiguration and ApplyConfiguration
     /// methods. The display_id may be unconfigured at the time this method is called.
     /// raw_eld is the ELD raw data formatted according to the HDA specification version 1.0a
     /// section 7.3.3.34.1.
     /// https://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/high-definition-audio-specification.pdf
     /// The driver must not retain references to the ELD after this function returns.
     SetEld(struct {
         display_id uint64;
         raw_eld vector<uint8>:MAX;
     }) -> ();

     // Connects the handle to the sysmem service.
     GetSysmemConnection(resource struct {
         sysmem_handle zx.handle:CHANNEL;
     }) -> (struct {
         s zx.status;
     });

     // Set sysmem buffer collection contraints needed to ensure an image can be imported with config
     // |config| on the fuchsia.sysmem.BufferCollection handle |collection|.
     SetBufferCollectionConstraints(struct {
         config Image;
         collection ZxUnownedHandle;
     }) -> (struct {
         s zx.status;
     });

     // Power off/on the display panel. Newly added displays are turned on by default.
     //
     // Displays that are turned off will not deliver VSync events.
     // This may include the vsync event for the most recently applied
     // config.
     SetDisplayPower(struct {
         display_id uint64;
         power_on bool;
     }) -> (struct {
         s zx.status;
     });
 };
	// Copyright 2018 The Fuchsia Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.
	library fuchsia.hardware.display.controller;

	using fuchsia.hardware.audiotypes;
	using zx;

	alias ZxPixelFormat = uint32;

	alias ZxUnownedHandle = uint32;

	type ImageType = strict enum : uint32 {
	/// The image is linear and VMO backed.
	SIMPLE = 0;

	// Intentionally left some gap between SIMPLE and CAPTURE.

	/// The image is used for capture
	CAPTURE = 10;
	};

	/// A structure containing information about an image.
	type Image = struct {
	/// The width and height of the image in pixels.
	width uint32;
	height uint32;

	/// The pixel format of the image.
	pixel_format ZxPixelFormat;

	/// The type conveys information about what is providing the pixel data. If this is not
	/// IMAGE_TYPE_SIMPLE, it is up to the driver and buffer producer to agree on the meaning
	/// of the value through some mechanism outside the scope of this API.
	type uint32;

	/// A driver-defined handle to the image. Each handle must be unique.
	handle uint64;
	};

	const INVALID_DISPLAY_ID uint32 = 0;
	const INVALID_ID uint32 = 0;
	const INVALID_CONFIG_STAMP_VALUE uint64 = 0;

	/// A unique stamp representing a unique set of display configuration
	/// in ApplyConfiguration().
	type ConfigStamp = struct {
	/// For valid configurations, the value should not be equal to
	/// `INVALID_CONFIG_STAMP_VALUE`.
	value uint64;
	};

	/// A fallback structure to convey display information without an edid.
	type DisplayParams = struct {
	width uint32;
	height uint32;
	refresh_rate_e2 uint32;
	};

	/// Info about valid cursor configurations.
	type CursorInfo = struct {
	/// The width and height of the cursor configuration, in pixels.
	width uint32;
	height uint32;
	format ZxPixelFormat;
	};

	type Panel = strict union {
	/// The bus_id to use to read this display's edid from the device's i2c protocol.
	1: i2c_bus_id uint32;
	/// The display's parameters if an edid is not present.
	2: params DisplayParams;
	};

	/// A structure containing information a connected display.
	type AddedDisplayArgs = struct {
	display_id uint64;

	/// A flag indicating whether or not the display has a valid edid.
	///
	/// If true, the device should expose an ZX_PROTOCOL_I2C_IMPL device through get_protocol, in
	/// addition to the ZX_PROTOCOL_DISPLAY_CONTROLLER_IMPL protocol. Note that the i2c device
	/// will be called from the on_displays_changed callback, so care should be taken to avoid
	/// deadlocks or double-locking.
	///
	/// If no edid is present, then the meaning of display_config's mode structure is
	/// undefined, and drivers should ignore it in check_configuration and apply_configuration.
	edid_present bool;
	panel Panel;

	/// A list of pixel formats supported by the display. The first entry is the
	/// preferred pixel format.
	pixel_format vector<ZxPixelFormat>:MAX;

	/// A list of cursor configurations most likely to be accepted by the driver. Can
	/// be null if cursor_count is 0.
	///
	/// The driver may reject some of these configurations in some circumstances, and
	/// it may accept other configurations, but at least one of these configurations
	/// should be valid at most times.
	cursor_info vector<CursorInfo>:MAX;
	};

	/// Out parameters will be populated before on_displays_changed returns.
	type AddedDisplayInfo = struct {
	is_hdmi_out bool;
	is_standard_srgb_out bool;

	audio_format_count uint32;

	/// All strings are null-terminated. \|manufacturer_id\| is guaranteed to have
	/// length 3, all other strings may be empty.
	manufacturer_id string:4;
	/// non-null
	manufacturer_name string:MAX;
	/// null-terminated
	monitor_name string:14;
	/// null-terminated
	monitor_serial string:14;

	// physical horizontal size in millimeters
	horizontal_size_mm uint32;
	// physical vertical size in millimeters
	vertical_size_mm uint32;
	};

	/// The client will not make any `ZX_PROTOCOL_DISPLAY_CONTROLLER_IMPL` calls into the device
	/// during these callbacks.
	@transport("Banjo")
	@banjo_layout("ddk-interface")
	protocol DisplayControllerInterface {
	/// Callbacks which are invoked when displays are added or removed. \|added_display_list\| and
	/// \|removed_display_list\| point to arrays of the display ids which were added and removed. If
	/// \|added_display_count\| or \|removed_display_count\| is 0, the corresponding array can be NULL.
	///
	/// The driver must be done accessing any images which were on the removed displays.
	///
	/// The driver should call this function when the callback is registered if any displays
	/// are present.
	OnDisplaysChanged(struct {
	added_display vector<AddedDisplayArgs>:MAX;
	removed_display vector<uint64>:MAX;
	}) -> (struct {
	display_info vector<AddedDisplayInfo>:MAX;
	});

	/// Events which are invoked when display vsync occurs.
	///
	/// Arguments
	/// - \|timestamp\|
	/// The ZX_CLOCK_MONOTONIC timestamp at which the vsync occurred.
	/// - \|config_stamp\|
	/// The config stamp of the latest configuration that is currently
	/// fully applied to all the layers of the display with `display_id`.
	/// If none of the configurations are currently fully applied to
	/// this display, a null value will be passed to the driver.
	/// Note that an `ApplyConfiguration()` call may contain multiple
	/// configurations with a certain `config_stamp`; Only the application
	/// status of the configuration with ID `display_id` is related.
	///
	/// The driver must call this function for all vsync events, even if the
	/// display has no images displayed.
	OnDisplayVsync(struct {
	display_id uint64;
	timestamp zx.time;
	config_stamp box<ConfigStamp>;
	}) -> ();

	GetAudioFormat(struct {
	display_id uint64;
	fmt_idx uint32;
	}) -> (struct {
	s zx.status;
	fmt fuchsia.hardware.audiotypes.AudioTypesAudioStreamFormatRange;
	});
	};

	type Alpha = strict enum : uint8 {
	DISABLE = 0;
	PREMULTIPLIED = 1;
	HW_MULTIPLY = 2;
	};

	/// Rotations are applied counter-clockwise, and are applied before reflections.
	type FrameTransform = strict enum : uint32 {
	IDENTITY = 0;
	REFLECT_X = 1;
	REFLECT_Y = 2;
	ROT_90 = 3;
	ROT_180 = 4;
	ROT_270 = 5;
	ROT_90_REFLECT_X = 6;
	ROT_90_REFLECT_Y = 7;
	};

	type Frame = struct {
	/// (\|x_pos\|, \|y_pos\|) specifies the position of the upper-left corner
	/// of the frame.
	x_pos uint32;
	y_pos uint32;
	width uint32;
	height uint32;
	};

	type PrimaryLayer = struct {
	image Image;

	/// An ALPHA_* constant.
	///
	/// If \|alpha_mode\| == `ALPHA_DISABLED`, the layer is opaque and alpha_layer_val is ignored.
	///
	/// If \|alpha_mode\| == `PREMULTIPLIED` or `HW_MULTIPLY` and \|alpha_layer_val\| is NaN, the alpha
	/// used when blending is determined by the per-pixel alpha channel.
	///
	/// If \|alpha_mode\| == `PREMULTIPLIED` or `HW_MULTIPLY` and \|alpha_layer_val\| is not NaN, the
	/// alpha used when blending is the product of alpha_layer_val and any per-pixel alpha.
	/// Additionally, if alpha_mode == PREMULTIPLIED, then the hardware must premultiply the color
	/// channel with alpha_layer_val before blending.
	///
	/// If alpha_layer_val is not NaN, it will be in the range [0, 1].
	alpha_mode Alpha;
	alpha_layer_val float32;

	transform_mode FrameTransform;

	/// The source frame, where (0,0) is the top-left corner of the image. The
	/// client guarantees that src_frame lies entirely within the image.
	src_frame Frame;

	/// The destination frame, where (0,0) is the top-left corner of the
	/// composed output. The client guarantees that dest_frame lies entirely
	/// within the composed output.
	dest_frame Frame;
	};

	type CursorLayer = struct {
	image Image;

	/// The position of the top-left corner of the cursor's image. When being
	/// applied to a display, the cursor is guaranteed to have at least one
	/// pixel of overlap with the display.
	x_pos int32;
	y_pos int32;
	};

	type ColorLayer = struct {
	format ZxPixelFormat;
	/// The color to use for the layer. The color is little-endian, and is
	/// guaranteed to be of the appropriate size.
	color vector<uint8>:MAX;
	};

	/// Types of layers.
	type LayerType = strict enum : uint32 {
	PRIMARY = 0;
	CURSOR = 1;
	COLOR = 2;
	};

	type LayerConfig = strict union {
	1: primary PrimaryLayer;
	2: cursor CursorLayer;
	3: color ColorLayer;
	};

	type Layer = struct {
	type LayerType;
	/// z_index of the layer. See \|check_configuration\| and \|apply_configuration\|.
	z_index uint32;
	cfg LayerConfig;
	};

	/// constants for display_config's mode_flags field
	type ModeFlag = strict enum : uint32 {
	VSYNC_POSITIVE = 0x1;
	HSYNC_POSITIVE = 0x2;
	INTERLACED = 0x4;
	ALTERNATING_VBLANK = 0x8;
	DOUBLE_CLOCKED = 0x10;
	};

	/// The video parameters which specify the display mode.
	type DisplayMode = struct {
	pixel_clock_10khz uint32;
	h_addressable uint32;
	h_front_porch uint32;
	h_sync_pulse uint32;
	h_blanking uint32;
	v_addressable uint32;
	v_front_porch uint32;
	v_sync_pulse uint32;
	v_blanking uint32;
	/// A bitmask of MODE_FLAG_* values
	flags uint32;
	};

	type ColorConversion = strict enum : uint32 {
	/// If set, use the 0 vector for the color conversion preoffset
	PREOFFSET = 0x1;
	/// If set, use the identity matrix for the color conversion coefficients
	COEFFICIENTS = 0x2;
	/// If set, use the 0 vector for the color conversion postoffset
	POSTOFFSET = 0x4;
	};

	type DisplayConfig = struct {
	/// the display id to which the configuration applies
	display_id uint64;

	mode DisplayMode;

	/// Bitmask of COLOR_CONVERSION_* flags
	cc_flags uint32;
	/// Color conversion is applied to each pixel according to the formula:
	///
	/// (cc_coefficients * (pixel + cc_preoffsets)) + cc_postoffsets
	///
	/// where pixel is a column vector consisting of the pixel's 3 components.
	cc_preoffsets array<float32, 3>;
	cc_coefficients array<array<float32, 3>, 3>;
	cc_postoffsets array<float32, 3>;

	@mutable
	@out_of_line_contents
	layer vector<Layer>:MAX;

	/// Flag to indicate valid gamma table
	gamma_table_present bool;
	/// Flag to indicate whether display driver should re-apply gamma correction table to hardware
	apply_gamma_table bool;
	/// Gamma Table (Red, Green and Blue)
	@mutable
	gamma_red vector<float32>:MAX;
	@mutable
	gamma_green vector<float32>:MAX;
	@mutable
	gamma_blue vector<float32>:MAX;
	};

	type ConfigDisplay = strict enum : uint32 {
	/// The display mode configuration is valid. Note that this is distinct from
	/// whether or not the layer configuration is valid.
	OK = 0;
	/// Error indicating that the hardware cannot simultaneously support the
	/// requested number of displays.
	TOO_MANY = 1;
	/// Error indicating that the hardware cannot simultaneously support the given
	/// set of display modes. To support a mode, the display must be able to display
	/// a single layer with width and height equal to the requested mode and the
	/// preferred pixel format.
	UNSUPPORTED_MODES = 2;
	};

	type Client = strict enum : uint32 {
	/// The client should convert the corresponding layer to a primary layer.
	USE_PRIMARY = 0x1;
	/// The client should compose all layers with MERGE_BASE and MERGE_SRC into a new,
	/// single primary layer at the MERGE_BASE layer's z-order. The driver must accept
	/// a fullscreen layer with the default pixel format, but may accept other layer
	/// parameters.
	///
	/// MERGE_BASE should only be set on one layer per display. If it is set on multiple
	/// layers, the client will arbitrarily pick one and change the rest to MERGE_SRC.
	MERGE_BASE = 0x2;
	MERGE_SRC = 0x4;
	/// The client should pre-scale the image so that src_frame's dimensions are equal
	/// to dest_frame's dimensions.
	FRAME_SCALE = 0x8;
	/// The client should pre-clip the image so that src_frame's dimensions are equal to
	/// the image's dimensions.
	SRC_FRAME = 0x10;
	/// The client should pre-apply the transformation so TRANSFORM_IDENTITY can be used.
	TRANSFORM = 0x20;
	/// The client should apply the color conversion.
	COLOR_CONVERSION = 0x40;
	/// The client should apply the alpha transformation itself.
	ALPHA = 0x80;
	/// The client cannot control the display gamma, and must accept
	/// the uncalibrated output. Clients are expected to produce linear
	/// buffers, and as such they cannot perform software gamma
	/// correction.
	GAMMA = 0x100;
	};

	/// The client guarantees that check_configuration and apply_configuration are always
	/// made from a single thread. The client makes no other threading guarantees.
	@transport("Banjo")
	@banjo_layout("ddk-protocol")
	protocol DisplayControllerImpl {
	/// The function will only be called once, and it will be called before any other
	/// functions are called.
	SetDisplayControllerInterface(resource struct {
	intf client_end:DisplayControllerInterface;
	}) -> ();

	/// Imports an image from a buffer collection into the driver. The driver should set
	/// image->handle.
	ImportImage(struct {
	@in_out
	image Image;
	collection ZxUnownedHandle;
	index uint32;
	}) -> (struct {
	s zx.status;
	});

	/// Releases any driver state associated with the given image. The client guarantees that
	/// any images passed to apply_config will not be released until a vsync occurs with a
	/// more recent image.
	ReleaseImage(struct {
	@in_out
	image Image;
	}) -> ();

	/// Validates the given configuration.
	///
	/// The configuration may not include all displays. Omitted displays should be treated as
	/// whichever of off or displaying a blank screen results in a more permissive validation.
	///
	/// All displays in a configuration will have at least one layer. The layers will be
	/// arranged in increasing z-order, and their z_index fields will be set consecutively.
	///
	/// Whether or not the driver can accept the configuration cannot depend on the
	/// particular image handles, as it must always be possible to present a new image in
	/// place of another image with a matching configuration. It also cannot depend on the
	/// cursor position, as that can be updated without another call to check_configuration.
	///
	/// display_cfg_result should be set to a CONFIG_DISPLAY_* error if the combination of
	/// display modes is not supported.
	///
	/// layer_cfg_result points to an array of arrays. The primary length is display_count, the
	/// secondary lengths are the corresponding display_cfg's layer_count. If display_cfg_result
	/// is CONFIG_DISPLAY_OK, any errors in layer configuration should be returned as a CLIENT*
	/// flag in the corresponding layer_cfg_result entry.
	///
	/// The driver must not retain references to the configuration after this function returns.
	/// TODO: Fix me...
	CheckConfiguration(struct {
	@inner_pointer
	display_config vector<DisplayConfig>:MAX;
	}) -> (struct {
	display_cfg_result uint32;
	@callee_allocated
	layer_cfg_result vector<uint32>:MAX;
	});

	/// Applies the configuration.
	///
	/// All configurations passed to this function will be derived from configurations which
	/// have been successfully validated, with the only differences either being omitted layers
	/// or different image handles. To account for any layers which are not present, the driver
	/// must use the z_index values of the present layers to configure them as if the whole
	/// configuration was present.
	///
	/// Unlike with check_configuration, displays included in the configuration are not
	/// guaranteed to include any layers. Both omitted displays and displays with no layers
	/// can either be turned off or set to display a blank screen, but for displays with no
	/// layers there is a strong preference to display a blank screen instead of turn them off.
	/// In either case, the driver must drop all references to old images and invoke the vsync
	/// callback after doing so.
	///
	/// `config_stamp` is a non-zero unique stamp to identify each configuration.
	/// Callers must guarantee that `config_stamp` is unique for each `ApplyConfiguration()`
	/// call.
	///
	/// The driver must not retain references to the configuration after this function returns.
	ApplyConfiguration(struct {
	@inner_pointer
	display_config vector<DisplayConfig>:MAX;
	config_stamp ConfigStamp;
	}) -> ();

	/// Set ELD for one display.
	///
	/// This method is called independently from the CheckConfiguration and ApplyConfiguration
	/// methods. The display_id may be unconfigured at the time this method is called.
	/// raw_eld is the ELD raw data formatted according to the HDA specification version 1.0a
	/// section 7.3.3.34.1.
	/// https://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/high-definition-audio-specification.pdf
	/// The driver must not retain references to the ELD after this function returns.
	SetEld(struct {
	display_id uint64;
	raw_eld vector<uint8>:MAX;
	}) -> ();

	// Connects the handle to the sysmem service.
	GetSysmemConnection(resource struct {
	sysmem_handle zx.handle:CHANNEL;
	}) -> (struct {
	s zx.status;
	});

	// Set sysmem buffer collection contraints needed to ensure an image can be imported with config
	// \|config\| on the fuchsia.sysmem.BufferCollection handle \|collection\|.
	SetBufferCollectionConstraints(struct {
	config Image;
	collection ZxUnownedHandle;
	}) -> (struct {
	s zx.status;
	});

	// Power off/on the display panel. Newly added displays are turned on by default.
	//
	// Displays that are turned off will not deliver VSync events.
	// This may include the vsync event for the most recently applied
	// config.
	SetDisplayPower(struct {
	display_id uint64;
	power_on bool;
	}) -> (struct {
	s zx.status;
	});
	};