text: /*
   * 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).
       *
       *
       * HWC_SIDEBAND
       *   Set by the caller before calling (*prepare)(), this value indicates
       *   the contents of this layer come from a sideband video stream.
       *
       *   The h/w composer is responsible for receiving new image buffers from
       *   the stream at the appropriate time (e.g. synchronized to a separate
       *   audio stream), compositing them with the current contents of other
       *   layers, and displaying the resulting image. This happens
       *   independently of the normal prepare/set cycle. The prepare/set calls
       *   only happen when other layers change, or when properties of the
       *   sideband layer such as position or size change.
       *
       *   If the h/w composer can't handle the layer as a sideband stream for
       *   some reason (e.g. unsupported scaling/blending/rotation, or too many
       *   sideband layers) it can set compositionType to HWC_FRAMEBUFFER in
       *   (*prepare)(). However, doing so will result in the layer being shown
       *   as a solid color since the platform is not currently able to composite
       *   sideband layers with the GPU. This may be improved in future
       *   versions of the platform.
       *
       *
       * HWC_CURSOR_OVERLAY
       *   Set by the HWC implementation during (*prepare)(), this value
       *   indicates the layer's composition will now be handled by the HWC.
       *   Additionally, the client can now asynchronously update the on-screen
       *   position of this layer using the setCursorPositionAsync() api.
       */
      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 {
              union {
                  /* When compositionType is HWC_FRAMEBUFFER, HWC_OVERLAY,
                   * HWC_FRAMEBUFFER_TARGET, this is the handle of the 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;
  
                  /* When compositionType is HWC_SIDEBAND, this is the handle
                   * of the sideband video stream to compose. */
                  const native_handle_t* sidebandStream;
              };
  
              /* 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;
  
              /* Region of the layer changed in the source buffer since
               * previous frame */
              hwc_rect_t dirtyRect;
  
              /* 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.
               *
               * HWC_SIDEBAND layers will never have an acquire fence, since
               * synchronization is handled through implementation-defined
               * sideband mechanisms.
               *
               * 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.
               *
               * Since HWC_SIDEBAND buffers don't pass through the HWC client,
               * the HWC 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];
          };
      };
  
  #ifdef __LP64__
      /*
       * For 64-bit mode, this struct is 120 bytes (and 8-byte aligned), and needs
       * to be padded as such to maintain binary compatibility.
       */
      uint8_t reserved[120 - 96];
  #else
      /*
       * For 32-bit mode, this struct is 96 bytes, and needs to be padded as such
       * to maintain binary compatibility.
       */
      uint8_t reserved[96 - 76];
  #endif
  
  } hwc_layer_1_t;
  
  #ifdef OMAP_ENHANCEMENT
  
  /*
   * HWC extension operations, see HWC_EXTENDED_API
   */
  enum {
      /*
       * Get extra layer data
       * @params
       * data: hwc_layer_extended_t
       */
      HWC_EXTENDED_OP_LAYERDATA = 1,
  
      /*
       * Returns layer stack identifier
       * @params
       * data: hwc_layer_stack_t
       */
      HWC_EXTENDED_OP_LAYERSTACK = 2,
  };
  
  typedef struct hwc_layer_extended {
      /*
       * Layer index (input)
       */
      uint32_t idx;
  
      /*
       * Display index (input)
       */
      int32_t dpy;
  
      /*
       * Provides a unique identity for this layer (output)
       */
      uint32_t identity;
  } hwc_layer_extended_t;
  
  typedef struct hwc_layer_stack {
      /*
       * Display index (input)
       */
      int32_t dpy;
  
      /*
       * Layer stack identifier for this display (output)
       */
      uint32_t stack;
  } hwc_layer_stack_t;
  
  typedef struct hwc_layer_list_extended {
      size_t numHwLayers;
      hwc_layer_extended_t hwLayers[0];
  } hwc_layer_list_extended_t;
  
  #endif
  
  /* 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,
  #ifdef OMAP_ENHANCEMENT
      /*
       * HWC_EXTENDED_API is set by SurfaceFlinger to indicate that the h/w
       * composer HAL api has been extended and that the HAL implementation
       * can use functions in the extended ABI.
       */
      HWC_EXTENDED_API = 0x80000000,
  #endif
  };
  
  /*
   * 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);
  
  #ifdef OMAP_ENHANCEMENT
      /*
       * (*extension_cb)() is called by the h/w composer HAL. Its purpose is
       * to extend the api from h/w composer to SurfaceFlinger.
       *
       * In order to handle mismatching build configuration between
       * SurfaceFlinger and the h/w composer HAL. The HAL will only call
       * this callback if HWC_EXTENDED_API is passed in hwc_layer_list_t
       * flags.
       *
       * The "operation" parameter specifies the specific extension required
       * the caller and callee should maintain the ABI between each other in
       * the same way as kernel ioctl calls do.
       *
       * If the "size" parameter is -1 a return value of zero indicates the
       * given operation is supported.
       */
      int (*extension_cb)(struct hwc_procs* procs,
                          int operation,
                          void** data,
                          int size);
  
  #endif
  
  } hwc_procs_t;
  
  
  /*****************************************************************************/
  
  typedef struct hwc_module {
      /**
       * Common methods of the hardware composer module.  This *must* be the first member of
       * hwc_module as users of this structure will cast a hw_module_t to
       * hwc_module pointer in contexts where it's known the hw_module_t references a
       * hwc_module.
       */
      struct hw_module_t common;
  } hwc_module_t;
  
  typedef struct hwc_composer_device_1 {
      /**
       * Common methods of the hardware composer device.  This *must* be the first member of
       * hwc_composer_device_1 as users of this structure will cast a hw_device_t to
       * hwc_composer_device_1 pointer in contexts where it's known the hw_device_t references a
       * 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, HWC_OVERLAY, or HWC_CURSOR_OVERLAY. For the
       * HWC_FRAMEBUFFER type, composition for the layer is handled by
       * SurfaceFlinger with OpenGL ES. For the latter two overlay types,
       * 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);
  
      union {
          /*
           * For HWC 1.3 and earlier, the blank() interface is used.
           *
           * 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);
  
          /*
           * For HWC 1.4 and above, setPowerMode() will be used in place of
           * blank().
           *
           * setPowerMode(..., mode)
           * Sets the display screen's power state.
           *
           * Refer to the documentation of the HWC_POWER_MODE_* constants
           * for information about each power mode.
           *
           * The functionality is similar to the blank() command in previous
           * versions of HWC, but with support for more power states.
           *
           * The display driver is expected to retain and restore the low power
           * state of the display while entering and exiting from suspend.
           *
           * Multiple sequential calls with the same mode value must be supported.
           *
           * The screen state transition must be be complete when the function
           * returns.
           *
           * returns 0 on success, negative on error.
           */
          int (*setPowerMode)(struct hwc_composer_device_1* dev, int disp,
                  int mode);
      };
  
      /*
       * 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.
       *
       * Hardware composers implementing HWC_DEVICE_API_VERSION_1_3 or prior
       * shall choose one configuration to activate and report it as the first
       * entry in the returned list. Reporting the inactive configurations is not
       * required.
       *
       * HWC_DEVICE_API_VERSION_1_4 and later provide configuration management
       * through SurfaceFlinger, and hardware composers implementing these APIs
       * must also provide getActiveConfig and setActiveConfig. Hardware composers
       * implementing these API versions may choose not to activate any
       * configuration, leaving configuration selection to higher levels of the
       * framework.
       *
       * Returns 0 on success or a negative error code on error. If disp is a
       * hotpluggable display type and no display is connected, an error shall be
       * returned.
       *
       * This field is REQUIRED for HWC_DEVICE_API_VERSION_1_1 and later.
       * It shall 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 shall 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
       * error code shall be returned.
       */
      int (*getDisplayAttributes)(struct hwc_composer_device_1* dev, int disp,
              uint32_t config, const uint32_t* attributes, int32_t* values);
  
      /*
       * (*getActiveConfig)() returns the index of the configuration that is
       * currently active on the connected display. The index is relative to
       * the list of configuration handles returned by getDisplayConfigs. If there
       * is no active configuration, -1 shall be returned.
       *
       * Returns the configuration index on success or -1 on error.
       *
       * This field is REQUIRED for HWC_DEVICE_API_VERSION_1_4 and later.
       * It shall be NULL for previous versions.
       */
      int (*getActiveConfig)(struct hwc_composer_device_1* dev, int disp);
  
      /*
       * (*setActiveConfig)() instructs the hardware composer to switch to the
       * display configuration at the given index in the list of configuration
       * handles returned by getDisplayConfigs.
       *
       * If this function returns without error, any subsequent calls to
       * getActiveConfig shall return the index set by this function until one
       * of the following occurs:
       *   1) Another successful call of this function
       *   2) The display is disconnected
       *
       * Returns 0 on success or a negative error code on error. If disp is a
       * hotpluggable display type and no display is connected, or if index is
       * outside of the range of hardware configurations returned by
       * getDisplayConfigs, an error shall be returned.
       *
       * This field is REQUIRED for HWC_DEVICE_API_VERSION_1_4 and later.
       * It shall be NULL for previous versions.
       */
      int (*setActiveConfig)(struct hwc_composer_device_1* dev, int disp,
              int index);
      /*
       * Asynchronously update the location of the cursor layer.
       *
       * Within the standard prepare()/set() composition loop, the client
       * (surfaceflinger) can request that a given layer uses dedicated cursor
       * composition hardware by specifiying the HWC_IS_CURSOR_LAYER flag. Only
       * one layer per display can have this flag set. If the layer is suitable
       * for the platform's cursor hardware, hwcomposer will return from prepare()
       * a composition type of HWC_CURSOR_OVERLAY for that layer. This indicates
       * not only that the client is not responsible for compositing that layer,
       * but also that the client can continue to update the position of that layer
       * after a call to set(). This can reduce the visible latency of mouse
       * movement to visible, on-screen cursor updates. Calls to
       * setCursorPositionAsync() may be made from a different thread doing the
       * prepare()/set() composition loop, but care must be taken to not interleave
       * calls of setCursorPositionAsync() between calls of set()/prepare().
       *
       * Notes:
       * - Only one layer per display can be specified as a cursor layer with
       *   HWC_IS_CURSOR_LAYER.
       * - hwcomposer will only return one layer per display as HWC_CURSOR_OVERLAY
       * - This returns 0 on success or -errno on error.
       * - This field is optional for HWC_DEVICE_API_VERSION_1_4 and later. It
       *   should be null for previous versions.
       */
      int (*setCursorPositionAsync)(struct hwc_composer_device_1 *dev, int disp, int x_pos, int y_pos);
  
      /*
       * Reserved for future use. Must be NULL.
       */
      void* reserved_proc[1];
  
  } 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 */
  