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platform_hardware_libhardware/include/hardware/hwcomposer.h
Jesse Hall 7ccf148f50 Update HWC documentation for virtual displays 
Bug: 8316155
Change-Id: I56598551b07082bfff90df160b103a4158e8c8c9
2013-11-13 14:48:15 -08:00

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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H
#define ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H
#include <stdint.h>
#include <sys/cdefs.h>
#include <hardware/gralloc.h>
#include <hardware/hardware.h>
#include <cutils/native_handle.h>
#include <hardware/hwcomposer_defs.h>
__BEGIN_DECLS
/*****************************************************************************/
/* for compatibility */
#define HWC_MODULE_API_VERSION HWC_MODULE_API_VERSION_0_1
#define HWC_DEVICE_API_VERSION HWC_DEVICE_API_VERSION_0_1
#define HWC_API_VERSION HWC_DEVICE_API_VERSION
/*****************************************************************************/
/**
* The id of this module
*/
#define HWC_HARDWARE_MODULE_ID "hwcomposer"
/**
* Name of the sensors device to open
*/
#define HWC_HARDWARE_COMPOSER "composer"
typedef struct hwc_rect {
int left;
int top;
int right;
int bottom;
} hwc_rect_t;
typedef struct hwc_frect {
float left;
float top;
float right;
float bottom;
} hwc_frect_t;
typedef struct hwc_region {
size_t numRects;
hwc_rect_t const* rects;
} hwc_region_t;
typedef struct hwc_color {
uint8_t r;
uint8_t g;
uint8_t b;
uint8_t a;
} hwc_color_t;
typedef struct hwc_layer_1 {
/*
* compositionType is used to specify this layer's type and is set by either
* the hardware composer implementation, or by the caller (see below).
*
* This field is always reset to HWC_BACKGROUND or HWC_FRAMEBUFFER
* before (*prepare)() is called when the HWC_GEOMETRY_CHANGED flag is
* also set, otherwise, this field is preserved between (*prepare)()
* calls.
*
* HWC_BACKGROUND
* Always set by the caller before calling (*prepare)(), this value
* indicates this is a special "background" layer. The only valid field
* is backgroundColor.
* The HWC can toggle this value to HWC_FRAMEBUFFER to indicate it CANNOT
* handle the background color.
*
*
* HWC_FRAMEBUFFER_TARGET
* Always set by the caller before calling (*prepare)(), this value
* indicates this layer is the framebuffer surface used as the target of
* OpenGL ES composition. If the HWC sets all other layers to HWC_OVERLAY
* or HWC_BACKGROUND, then no OpenGL ES composition will be done, and
* this layer should be ignored during set().
*
* This flag (and the framebuffer surface layer) will only be used if the
* HWC version is HWC_DEVICE_API_VERSION_1_1 or higher. In older versions,
* the OpenGL ES target surface is communicated by the (dpy, sur) fields
* in hwc_compositor_device_1_t.
*
* This value cannot be set by the HWC implementation.
*
*
* HWC_FRAMEBUFFER
* Set by the caller before calling (*prepare)() ONLY when the
* HWC_GEOMETRY_CHANGED flag is also set.
*
* Set by the HWC implementation during (*prepare)(), this indicates
* that the layer will be drawn into the framebuffer using OpenGL ES.
* The HWC can toggle this value to HWC_OVERLAY to indicate it will
* handle the layer.
*
*
* HWC_OVERLAY
* Set by the HWC implementation during (*prepare)(), this indicates
* that the layer will be handled by the HWC (ie: it must not be
* composited with OpenGL ES).
*
*/
int32_t compositionType;
/*
* hints is bit mask set by the HWC implementation during (*prepare)().
* It is preserved between (*prepare)() calls, unless the
* HWC_GEOMETRY_CHANGED flag is set, in which case it is reset to 0.
*
* see hwc_layer_t::hints
*/
uint32_t hints;
/* see hwc_layer_t::flags */
uint32_t flags;
union {
/* color of the background. hwc_color_t.a is ignored */
hwc_color_t backgroundColor;
struct {
/* handle of buffer to compose. This handle is guaranteed to have been
* allocated from gralloc using the GRALLOC_USAGE_HW_COMPOSER usage flag. If
* the layer's handle is unchanged across two consecutive prepare calls and
* the HWC_GEOMETRY_CHANGED flag is not set for the second call then the
* HWComposer implementation may assume that the contents of the buffer have
* not changed. */
buffer_handle_t handle;
/* transformation to apply to the buffer during composition */
uint32_t transform;
/* blending to apply during composition */
int32_t blending;
/* area of the source to consider, the origin is the top-left corner of
* the buffer. As of HWC_DEVICE_API_VERSION_1_3, sourceRect uses floats.
* If the h/w can't support a non-integer source crop rectangle, it should
* punt to OpenGL ES composition.
*/
union {
// crop rectangle in integer (pre HWC_DEVICE_API_VERSION_1_3)
hwc_rect_t sourceCropi;
hwc_rect_t sourceCrop; // just for source compatibility
// crop rectangle in floats (as of HWC_DEVICE_API_VERSION_1_3)
hwc_frect_t sourceCropf;
};
/* where to composite the sourceCrop onto the display. The sourceCrop
* is scaled using linear filtering to the displayFrame. The origin is the
* top-left corner of the screen.
*/
hwc_rect_t displayFrame;
/* visible region in screen space. The origin is the
* top-left corner of the screen.
* The visible region INCLUDES areas overlapped by a translucent layer.
*/
hwc_region_t visibleRegionScreen;
/* Sync fence object that will be signaled when the buffer's
* contents are available. May be -1 if the contents are already
* available. This field is only valid during set(), and should be
* ignored during prepare(). The set() call must not wait for the
* fence to be signaled before returning, but the HWC must wait for
* all buffers to be signaled before reading from them.
*
* HWC_FRAMEBUFFER layers will never have an acquire fence, since
* reads from them are complete before the framebuffer is ready for
* display.
*
* The HWC takes ownership of the acquireFenceFd and is responsible
* for closing it when no longer needed.
*/
int acquireFenceFd;
/* During set() the HWC must set this field to a file descriptor for
* a sync fence object that will signal after the HWC has finished
* reading from the buffer. The field is ignored by prepare(). Each
* layer should have a unique file descriptor, even if more than one
* refer to the same underlying fence object; this allows each to be
* closed independently.
*
* If buffer reads can complete at significantly different times,
* then using independent fences is preferred. For example, if the
* HWC handles some layers with a blit engine and others with
* overlays, then the blit layers can be reused immediately after
* the blit completes, but the overlay layers can't be reused until
* a subsequent frame has been displayed.
*
* Since HWC doesn't read from HWC_FRAMEBUFFER layers, it shouldn't
* produce a release fence for them. The releaseFenceFd will be -1
* for these layers when set() is called.
*
* The HWC client taks ownership of the releaseFenceFd and is
* responsible for closing it when no longer needed.
*/
int releaseFenceFd;
/*
* Availability: HWC_DEVICE_API_VERSION_1_2
*
* Alpha value applied to the whole layer. The effective
* value of each pixel is computed as:
*
* if (blending == HWC_BLENDING_PREMULT)
* pixel.rgb = pixel.rgb * planeAlpha / 255
* pixel.a = pixel.a * planeAlpha / 255
*
* Then blending proceeds as usual according to the "blending"
* field above.
*
* NOTE: planeAlpha applies to YUV layers as well:
*
* pixel.rgb = yuv_to_rgb(pixel.yuv)
* if (blending == HWC_BLENDING_PREMULT)
* pixel.rgb = pixel.rgb * planeAlpha / 255
* pixel.a = planeAlpha
*
*
* IMPLEMENTATION NOTE:
*
* If the source image doesn't have an alpha channel, then
* the h/w can use the HWC_BLENDING_COVERAGE equations instead of
* HWC_BLENDING_PREMULT and simply set the alpha channel to
* planeAlpha.
*
* e.g.:
*
* if (blending == HWC_BLENDING_PREMULT)
* blending = HWC_BLENDING_COVERAGE;
* pixel.a = planeAlpha;
*
*/
uint8_t planeAlpha;
/* reserved for future use */
uint8_t _pad[3];
};
};
/* Allow for expansion w/o breaking binary compatibility.
* Pad layer to 96 bytes, assuming 32-bit pointers.
*/
int32_t reserved[24 - 19];
} hwc_layer_1_t;
/* This represents a display, typically an EGLDisplay object */
typedef void* hwc_display_t;
/* This represents a surface, typically an EGLSurface object */
typedef void* hwc_surface_t;
/*
* hwc_display_contents_1_t::flags values
*/
enum {
/*
* HWC_GEOMETRY_CHANGED is set by SurfaceFlinger to indicate that the list
* passed to (*prepare)() has changed by more than just the buffer handles
* and acquire fences.
*/
HWC_GEOMETRY_CHANGED = 0x00000001,
};
/*
* Description of the contents to output on a display.
*
* This is the top-level structure passed to the prepare and set calls to
* negotiate and commit the composition of a display image.
*/
typedef struct hwc_display_contents_1 {
/* File descriptor referring to a Sync HAL fence object which will signal
* when this composition is retired. For a physical display, a composition
* is retired when it has been replaced on-screen by a subsequent set. For
* a virtual display, the composition is retired when the writes to
* outputBuffer are complete and can be read. The fence object is created
* and returned by the set call; this field will be -1 on entry to prepare
* and set. SurfaceFlinger will close the returned file descriptor.
*/
int retireFenceFd;
union {
/* Fields only relevant for HWC_DEVICE_VERSION_1_0. */
struct {
/* (dpy, sur) is the target of SurfaceFlinger's OpenGL ES
* composition for HWC_DEVICE_VERSION_1_0. They aren't relevant to
* prepare. The set call should commit this surface atomically to
* the display along with any overlay layers.
*/
hwc_display_t dpy;
hwc_surface_t sur;
};
/* These fields are used for virtual displays when the h/w composer
* version is at least HWC_DEVICE_VERSION_1_3. */
struct {
/* outbuf is the buffer that receives the composed image for
* virtual displays. Writes to the outbuf must wait until
* outbufAcquireFenceFd signals. A fence that will signal when
* writes to outbuf are complete should be returned in
* retireFenceFd.
*
* This field is set before prepare(), so properties of the buffer
* can be used to decide which layers can be handled by h/w
* composer.
*
* If prepare() sets all layers to FRAMEBUFFER, then GLES
* composition will happen directly to the output buffer. In this
* case, both outbuf and the FRAMEBUFFER_TARGET layer's buffer will
* be the same, and set() has no work to do besides managing fences.
*
* If the TARGET_FORCE_HWC_FOR_VIRTUAL_DISPLAYS board config
* variable is defined (not the default), then this behavior is
* changed: if all layers are marked for FRAMEBUFFER, GLES
* composition will take place to a scratch framebuffer, and
* h/w composer must copy it to the output buffer. This allows the
* h/w composer to do format conversion if there are cases where
* that is more desirable than doing it in the GLES driver or at the
* virtual display consumer.
*
* If some or all layers are marked OVERLAY, then the framebuffer
* and output buffer will be different. As with physical displays,
* the framebuffer handle will not change between frames if all
* layers are marked for OVERLAY.
*/
buffer_handle_t outbuf;
/* File descriptor for a fence that will signal when outbuf is
* ready to be written. The h/w composer is responsible for closing
* this when no longer needed.
*
* Will be -1 whenever outbuf is NULL, or when the outbuf can be
* written immediately.
*/
int outbufAcquireFenceFd;
};
};
/* List of layers that will be composed on the display. The buffer handles
* in the list will be unique. If numHwLayers is 0, all composition will be
* performed by SurfaceFlinger.
*/
uint32_t flags;
size_t numHwLayers;
hwc_layer_1_t hwLayers[0];
} hwc_display_contents_1_t;
/* see hwc_composer_device::registerProcs()
* All of the callbacks are required and non-NULL unless otherwise noted.
*/
typedef struct hwc_procs {
/*
* (*invalidate)() triggers a screen refresh, in particular prepare and set
* will be called shortly after this call is made. Note that there is
* NO GUARANTEE that the screen refresh will happen after invalidate()
* returns (in particular, it could happen before).
* invalidate() is GUARANTEED TO NOT CALL BACK into the h/w composer HAL and
* it is safe to call invalidate() from any of hwc_composer_device
* hooks, unless noted otherwise.
*/
void (*invalidate)(const struct hwc_procs* procs);
/*
* (*vsync)() is called by the h/w composer HAL when a vsync event is
* received and HWC_EVENT_VSYNC is enabled on a display
* (see: hwc_event_control).
*
* the "disp" parameter indicates which display the vsync event is for.
* the "timestamp" parameter is the system monotonic clock timestamp in
* nanosecond of when the vsync event happened.
*
* vsync() is GUARANTEED TO NOT CALL BACK into the h/w composer HAL.
*
* It is expected that vsync() is called from a thread of at least
* HAL_PRIORITY_URGENT_DISPLAY with as little latency as possible,
* typically less than 0.5 ms.
*
* It is a (silent) error to have HWC_EVENT_VSYNC enabled when calling
* hwc_composer_device.set(..., 0, 0, 0) (screen off). The implementation
* can either stop or continue to process VSYNC events, but must not
* crash or cause other problems.
*/
void (*vsync)(const struct hwc_procs* procs, int disp, int64_t timestamp);
/*
* (*hotplug)() is called by the h/w composer HAL when a display is
* connected or disconnected. The PRIMARY display is always connected and
* the hotplug callback should not be called for it.
*
* The disp parameter indicates which display type this event is for.
* The connected parameter indicates whether the display has just been
* connected (1) or disconnected (0).
*
* The hotplug() callback may call back into the h/w composer on the same
* thread to query refresh rate and dpi for the display. Additionally,
* other threads may be calling into the h/w composer while the callback
* is in progress.
*
* The h/w composer must serialize calls to the hotplug callback; only
* one thread may call it at a time.
*
* This callback will be NULL if the h/w composer is using
* HWC_DEVICE_API_VERSION_1_0.
*/
void (*hotplug)(const struct hwc_procs* procs, int disp, int connected);
} hwc_procs_t;
/*****************************************************************************/
typedef struct hwc_module {
struct hw_module_t common;
} hwc_module_t;
typedef struct hwc_composer_device_1 {
struct hw_device_t common;
/*
* (*prepare)() is called for each frame before composition and is used by
* SurfaceFlinger to determine what composition steps the HWC can handle.
*
* (*prepare)() can be called more than once, the last call prevails.
*
* The HWC responds by setting the compositionType field in each layer to
* either HWC_FRAMEBUFFER or HWC_OVERLAY. In the former case, the
* composition for the layer is handled by SurfaceFlinger with OpenGL ES,
* in the later case, the HWC will have to handle the layer's composition.
* compositionType and hints are preserved between (*prepare)() calles
* unless the HWC_GEOMETRY_CHANGED flag is set.
*
* (*prepare)() is called with HWC_GEOMETRY_CHANGED to indicate that the
* list's geometry has changed, that is, when more than just the buffer's
* handles have been updated. Typically this happens (but is not limited to)
* when a window is added, removed, resized or moved. In this case
* compositionType and hints are reset to their default value.
*
* For HWC 1.0, numDisplays will always be one, and displays[0] will be
* non-NULL.
*
* For HWC 1.1, numDisplays will always be HWC_NUM_PHYSICAL_DISPLAY_TYPES.
* Entries for unsupported or disabled/disconnected display types will be
* NULL.
*
* In HWC 1.3, numDisplays may be up to HWC_NUM_DISPLAY_TYPES. The extra
* entries correspond to enabled virtual displays, and will be non-NULL.
*
* returns: 0 on success. An negative error code on error. If an error is
* returned, SurfaceFlinger will assume that none of the layer will be
* handled by the HWC.
*/
int (*prepare)(struct hwc_composer_device_1 *dev,
size_t numDisplays, hwc_display_contents_1_t** displays);
/*
* (*set)() is used in place of eglSwapBuffers(), and assumes the same
* functionality, except it also commits the work list atomically with
* the actual eglSwapBuffers().
*
* The layer lists are guaranteed to be the same as the ones returned from
* the last call to (*prepare)().
*
* When this call returns the caller assumes that the displays will be
* updated in the near future with the content of their work lists, without
* artifacts during the transition from the previous frame.
*
* A display with zero layers indicates that the entire composition has
* been handled by SurfaceFlinger with OpenGL ES. In this case, (*set)()
* behaves just like eglSwapBuffers().
*
* For HWC 1.0, numDisplays will always be one, and displays[0] will be
* non-NULL.
*
* For HWC 1.1, numDisplays will always be HWC_NUM_PHYSICAL_DISPLAY_TYPES.
* Entries for unsupported or disabled/disconnected display types will be
* NULL.
*
* In HWC 1.3, numDisplays may be up to HWC_NUM_DISPLAY_TYPES. The extra
* entries correspond to enabled virtual displays, and will be non-NULL.
*
* IMPORTANT NOTE: There is an implicit layer containing opaque black
* pixels behind all the layers in the list. It is the responsibility of
* the hwcomposer module to make sure black pixels are output (or blended
* from).
*
* IMPORTANT NOTE: In the event of an error this call *MUST* still cause
* any fences returned in the previous call to set to eventually become
* signaled. The caller may have already issued wait commands on these
* fences, and having set return without causing those fences to signal
* will likely result in a deadlock.
*
* returns: 0 on success. A negative error code on error:
* HWC_EGL_ERROR: eglGetError() will provide the proper error code (only
* allowed prior to HWComposer 1.1)
* Another code for non EGL errors.
*/
int (*set)(struct hwc_composer_device_1 *dev,
size_t numDisplays, hwc_display_contents_1_t** displays);
/*
* eventControl(..., event, enabled)
* Enables or disables h/w composer events for a display.
*
* eventControl can be called from any thread and takes effect
* immediately.
*
* Supported events are:
* HWC_EVENT_VSYNC
*
* returns -EINVAL if the "event" parameter is not one of the value above
* or if the "enabled" parameter is not 0 or 1.
*/
int (*eventControl)(struct hwc_composer_device_1* dev, int disp,
int event, int enabled);
/*
* blank(..., blank)
* Blanks or unblanks a display's screen.
*
* Turns the screen off when blank is nonzero, on when blank is zero.
* Multiple sequential calls with the same blank value must be supported.
* The screen state transition must be be complete when the function
* returns.
*
* returns 0 on success, negative on error.
*/
int (*blank)(struct hwc_composer_device_1* dev, int disp, int blank);
/*
* Used to retrieve information about the h/w composer
*
* Returns 0 on success or -errno on error.
*/
int (*query)(struct hwc_composer_device_1* dev, int what, int* value);
/*
* (*registerProcs)() registers callbacks that the h/w composer HAL can
* later use. It will be called immediately after the composer device is
* opened with non-NULL procs. It is FORBIDDEN to call any of the callbacks
* from within registerProcs(). registerProcs() must save the hwc_procs_t
* pointer which is needed when calling a registered callback.
*/
void (*registerProcs)(struct hwc_composer_device_1* dev,
hwc_procs_t const* procs);
/*
* This field is OPTIONAL and can be NULL.
*
* If non NULL it will be called by SurfaceFlinger on dumpsys
*/
void (*dump)(struct hwc_composer_device_1* dev, char *buff, int buff_len);
/*
* (*getDisplayConfigs)() returns handles for the configurations available
* on the connected display. These handles must remain valid as long as the
* display is connected.
*
* Configuration handles are written to configs. The number of entries
* allocated by the caller is passed in *numConfigs; getDisplayConfigs must
* not try to write more than this number of config handles. On return, the
* total number of configurations available for the display is returned in
* *numConfigs. If *numConfigs is zero on entry, then configs may be NULL.
*
* HWC_DEVICE_API_VERSION_1_1 does not provide a way to choose a config.
* For displays that support multiple configurations, the h/w composer
* implementation should choose one and report it as the first config in
* the list. Reporting the not-chosen configs is not required.
*
* Returns 0 on success or -errno on error. If disp is a hotpluggable
* display type and no display is connected, an error should be returned.
*
* This field is REQUIRED for HWC_DEVICE_API_VERSION_1_1 and later.
* It should be NULL for previous versions.
*/
int (*getDisplayConfigs)(struct hwc_composer_device_1* dev, int disp,
uint32_t* configs, size_t* numConfigs);
/*
* (*getDisplayAttributes)() returns attributes for a specific config of a
* connected display. The config parameter is one of the config handles
* returned by getDisplayConfigs.
*
* The list of attributes to return is provided in the attributes
* parameter, terminated by HWC_DISPLAY_NO_ATTRIBUTE. The value for each
* requested attribute is written in order to the values array. The
* HWC_DISPLAY_NO_ATTRIBUTE attribute does not have a value, so the values
* array will have one less value than the attributes array.
*
* This field is REQUIRED for HWC_DEVICE_API_VERSION_1_1 and later.
* It should be NULL for previous versions.
*
* If disp is a hotpluggable display type and no display is connected,
* or if config is not a valid configuration for the display, a negative
* value should be returned.
*/
int (*getDisplayAttributes)(struct hwc_composer_device_1* dev, int disp,
uint32_t config, const uint32_t* attributes, int32_t* values);
/*
* Reserved for future use. Must be NULL.
*/
void* reserved_proc[4];
} hwc_composer_device_1_t;
/** convenience API for opening and closing a device */
static inline int hwc_open_1(const struct hw_module_t* module,
hwc_composer_device_1_t** device) {
return module->methods->open(module,
HWC_HARDWARE_COMPOSER, (struct hw_device_t**)device);
}
static inline int hwc_close_1(hwc_composer_device_1_t* device) {
return device->common.close(&device->common);
}
/*****************************************************************************/
__END_DECLS
#endif /* ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H */
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