6.12. EGL Interoperability

This section describes the EGL interoperability functions of the low-level CUDA driver application programming interface.

Functions

CUresult cuEGLStreamConsumerAcquireFrame(CUeglStreamConnection *conn, CUgraphicsResource *pCudaResource, CUstream *pStream, unsigned int timeout): Acquire an image frame from the EGLStream with CUDA as a consumer.
CUresult cuEGLStreamConsumerConnect(CUeglStreamConnection *conn, EGLStreamKHR stream): Connect CUDA to EGLStream as a consumer.
CUresult cuEGLStreamConsumerConnectWithFlags(CUeglStreamConnection *conn, EGLStreamKHR stream, unsigned int flags): Connect CUDA to EGLStream as a consumer with given flags.
CUresult cuEGLStreamConsumerDisconnect(CUeglStreamConnection *conn): Disconnect CUDA as a consumer to EGLStream .
CUresult cuEGLStreamConsumerReleaseFrame(CUeglStreamConnection *conn, CUgraphicsResource pCudaResource, CUstream *pStream): Releases the last frame acquired from the EGLStream.
CUresult cuEGLStreamProducerConnect(CUeglStreamConnection *conn, EGLStreamKHR stream, EGLint width, EGLint height): Connect CUDA to EGLStream as a producer.
CUresult cuEGLStreamProducerDisconnect(CUeglStreamConnection *conn): Disconnect CUDA as a producer to EGLStream .
CUresult cuEGLStreamProducerPresentFrame(CUeglStreamConnection *conn, CUeglFrame eglframe, CUstream *pStream): Present a CUDA eglFrame to the EGLStream with CUDA as a producer.
CUresult cuEGLStreamProducerReturnFrame(CUeglStreamConnection *conn, CUeglFrame *eglframe, CUstream *pStream): Return the CUDA eglFrame to the EGLStream released by the consumer.
CUresult cuEventCreateFromEGLSync(CUevent *phEvent, EGLSyncKHR eglSync, unsigned int flags): Creates an event from EGLSync object.
CUresult cuGraphicsEGLRegisterImage(CUgraphicsResource *pCudaResource, EGLImageKHR image, unsigned int flags): Registers an EGL image.
CUresult cuGraphicsResourceGetMappedEglFrame(CUeglFrame *eglFrame, CUgraphicsResource resource, unsigned int index, unsigned int mipLevel): Get an eglFrame through which to access a registered EGL graphics resource.

6.12.1. Functions

CUresult cuEGLStreamConsumerAcquireFrame(CUeglStreamConnection *conn, CUgraphicsResource *pCudaResource, CUstream *pStream, unsigned int timeout)

Acquire an image frame from the EGLStream with CUDA as a consumer.

Acquire an image frame from EGLStreamKHR. This API can also acquire an old frame presented by the producer unless explicitly disabled by setting EGL_SUPPORT_REUSE_NV flag to EGL_FALSE during stream initialization. By default, EGLStream is created with this flag set to EGL_TRUE. cuGraphicsResourceGetMappedEglFrame can be called on pCudaResource to get CUeglFrame.

Parameters

conn – - Connection on which to acquire
pCudaResource – - CUDA resource on which the stream frame will be mapped for use.
pStream – - CUDA stream for synchronization and any data migrations implied by CUeglResourceLocationFlags.
timeout – - Desired timeout in usec for a new frame to be acquired. If set as CUDA_EGL_INFINITE_TIMEOUT, acquire waits infinitely. After timeout occurs CUDA consumer tries to acquire an old frame if available and EGL_SUPPORT_REUSE_NV flag is set.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_LAUNCH_TIMEOUT,

CUresult cuEGLStreamConsumerConnect(CUeglStreamConnection *conn, EGLStreamKHR stream)

Connect CUDA to EGLStream as a consumer.

Connect CUDA as a consumer to EGLStreamKHR specified by stream.

The EGLStreamKHR is an EGL object that transfers a sequence of image frames from one API to another.

Parameters

conn – - Pointer to the returned connection handle
stream – - EGLStreamKHR handle

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuEGLStreamConsumerConnectWithFlags(CUeglStreamConnection *conn, EGLStreamKHR stream, unsigned int flags)

Connect CUDA to EGLStream as a consumer with given flags.

Connect CUDA as a consumer to EGLStreamKHR specified by stream with specified flags defined by CUeglResourceLocationFlags.

The flags specify whether the consumer wants to access frames from system memory or video memory. Default is CU_EGL_RESOURCE_LOCATION_VIDMEM.

Parameters

conn – - Pointer to the returned connection handle
stream – - EGLStreamKHR handle
flags – - Flags denote intended location - system or video.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuEGLStreamConsumerDisconnect(CUeglStreamConnection *conn)

Disconnect CUDA as a consumer to EGLStream .

Disconnect CUDA as a consumer to EGLStreamKHR.

Parameters: conn – - Conection to disconnect.
Returns: CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuEGLStreamConsumerReleaseFrame(CUeglStreamConnection *conn, CUgraphicsResource pCudaResource, CUstream *pStream)

Releases the last frame acquired from the EGLStream.

Release the acquired image frame specified by pCudaResource to EGLStreamKHR. If EGL_SUPPORT_REUSE_NV flag is set to EGL_TRUE, at the time of EGL creation this API doesn’t release the last frame acquired on the EGLStream. By default, EGLStream is created with this flag set to EGL_TRUE.

Parameters

conn – - Connection on which to release
pCudaResource – - CUDA resource whose corresponding frame is to be released
pStream – - CUDA stream on which release will be done.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE,

CUresult cuEGLStreamProducerConnect(CUeglStreamConnection *conn, EGLStreamKHR stream, EGLint width, EGLint height)

Connect CUDA to EGLStream as a producer.

Connect CUDA as a producer to EGLStreamKHR specified by stream.

The EGLStreamKHR is an EGL object that transfers a sequence of image frames from one API to another.

Parameters

conn – - Pointer to the returned connection handle
stream – - EGLStreamKHR handle
width – - width of the image to be submitted to the stream
height – - height of the image to be submitted to the stream

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuEGLStreamProducerDisconnect(CUeglStreamConnection *conn)

Disconnect CUDA as a producer to EGLStream .

Disconnect CUDA as a producer to EGLStreamKHR.

See also

cuEGLStreamProducerConnect, cuEGLStreamProducerDisconnect, cuEGLStreamProducerPresentFrame, ::cudaEGLStreamProducerDisconnect

Parameters: conn – - Conection to disconnect.
Returns: CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuEGLStreamProducerPresentFrame(CUeglStreamConnection *conn, CUeglFrame eglframe, CUstream *pStream)

Present a CUDA eglFrame to the EGLStream with CUDA as a producer.

When a frame is presented by the producer, it gets associated with the EGLStream and thus it is illegal to free the frame before the producer is disconnected. If a frame is freed and reused it may lead to undefined behavior.

If producer and consumer are on different GPUs (iGPU and dGPU) then frametype CU_EGL_FRAME_TYPE_ARRAY is not supported. CU_EGL_FRAME_TYPE_PITCH can be used for such cross-device applications.

The CUeglFrame is defined as:

typedef struct CUeglFrame_st {
    union {
        CUarray pArray[MAX_PLANES];
        void*   pPitch[MAX_PLANES];
    } frame;
    unsigned int width;
    unsigned int height;
    unsigned int depth;
    unsigned int pitch;
    unsigned int planeCount;
    unsigned int numChannels;
    CUeglFrameType frameType;
    CUeglColorFormat eglColorFormat;
    CUarray_format cuFormat;
} CUeglFrame;

For CUeglFrame of type CU_EGL_FRAME_TYPE_PITCH, the application may present sub-region of a memory allocation. In that case, the pitched pointer will specify the start address of the sub-region in the allocation and corresponding CUeglFrame fields will specify the dimensions of the sub-region.

See also

cuEGLStreamProducerConnect, cuEGLStreamProducerDisconnect, cuEGLStreamProducerReturnFrame, ::cudaEGLStreamProducerPresentFrame

Parameters

conn – - Connection on which to present the CUDA array
eglframe – - CUDA Eglstream Proucer Frame handle to be sent to the consumer over EglStream.
pStream – - CUDA stream on which to present the frame.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE,

CUresult cuEGLStreamProducerReturnFrame(CUeglStreamConnection *conn, CUeglFrame *eglframe, CUstream *pStream)

Return the CUDA eglFrame to the EGLStream released by the consumer.

This API can potentially return CUDA_ERROR_LAUNCH_TIMEOUT if the consumer has not returned a frame to EGL stream. If timeout is returned the application can retry.

See also

cuEGLStreamProducerConnect, cuEGLStreamProducerDisconnect, cuEGLStreamProducerPresentFrame, ::cudaEGLStreamProducerReturnFrame

Parameters

conn – - Connection on which to return
eglframe – - CUDA Eglstream Proucer Frame handle returned from the consumer over EglStream.
pStream – - CUDA stream on which to return the frame.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_LAUNCH_TIMEOUT

CUresult cuEventCreateFromEGLSync(CUevent *phEvent, EGLSyncKHR eglSync, unsigned int flags)

Creates an event from EGLSync object.

Creates an event *phEvent from an EGLSyncKHR eglSync with the flags specified via flags. Valid flags include:

CU_EVENT_DEFAULT: Default event creation flag.
CU_EVENT_BLOCKING_SYNC: Specifies that the created event should use blocking synchronization. A CPU thread that uses cuEventSynchronize() to wait on an event created with this flag will block until the event has actually been completed.

Once the eglSync gets destroyed, cuEventDestroy is the only API that can be invoked on the event.

cuEventRecord and TimingData are not supported for events created from EGLSync.

The EGLSyncKHR is an opaque handle to an EGL sync object. typedef void* EGLSyncKHR

See also

cuEventQuery, cuEventSynchronize, cuEventDestroy

Parameters

phEvent – - Returns newly created event
eglSync – - Opaque handle to EGLSync object
flags – - Event creation flags

Returns

CUDA_SUCCESS, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_INVALID_CONTEXT, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_OUT_OF_MEMORY

CUresult cuGraphicsEGLRegisterImage(CUgraphicsResource *pCudaResource, EGLImageKHR image, unsigned int flags)

Registers an EGL image.

Registers the EGLImageKHR specified by image for access by CUDA. A handle to the registered object is returned as pCudaResource. Additional Mapping/Unmapping is not required for the registered resource and cuGraphicsResourceGetMappedEglFrame can be directly called on the pCudaResource.

The application will be responsible for synchronizing access to shared objects. The application must ensure that any pending operation which access the objects have completed before passing control to CUDA. This may be accomplished by issuing and waiting for glFinish command on all GLcontexts (for OpenGL and likewise for other APIs). The application will be also responsible for ensuring that any pending operation on the registered CUDA resource has completed prior to executing subsequent commands in other APIs accesing the same memory objects. This can be accomplished by calling cuCtxSynchronize or cuEventSynchronize (preferably).

The surface’s intended usage is specified using flags, as follows:

CU_GRAPHICS_MAP_RESOURCE_FLAGS_NONE: Specifies no hints about how this resource will be used. It is therefore assumed that this resource will be read from and written to by CUDA. This is the default value.
CU_GRAPHICS_MAP_RESOURCE_FLAGS_READ_ONLY: Specifies that CUDA will not write to this resource.
CU_GRAPHICS_MAP_RESOURCE_FLAGS_WRITE_DISCARD: Specifies that CUDA will not read from this resource and will write over the entire contents of the resource, so none of the data previously stored in the resource will be preserved.

The EGLImageKHR is an object which can be used to create EGLImage target resource. It is defined as a void pointer. typedef void* EGLImageKHR

See also

cuGraphicsEGLRegisterImage, cuGraphicsUnregisterResource, cuGraphicsResourceSetMapFlags, cuGraphicsMapResources, cuGraphicsUnmapResources, ::cudaGraphicsEGLRegisterImage

Parameters

pCudaResource – - Pointer to the returned object handle
image – - An EGLImageKHR image which can be used to create target resource.
flags – - Map flags

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_ALREADY_MAPPED, CUDA_ERROR_INVALID_CONTEXT,

CUresult cuGraphicsResourceGetMappedEglFrame(CUeglFrame *eglFrame, CUgraphicsResource resource, unsigned int index, unsigned int mipLevel)

Get an eglFrame through which to access a registered EGL graphics resource.

Returns in *eglFrame an eglFrame pointer through which the registered graphics resource resource may be accessed. This API can only be called for registered EGL graphics resources.

The CUeglFrame is defined as:

typedef struct CUeglFrame_st {
    union {
        CUarray pArray[MAX_PLANES];
        void*   pPitch[MAX_PLANES];
    } frame;
    unsigned int width;
    unsigned int height;
    unsigned int depth;
    unsigned int pitch;
    unsigned int planeCount;
    unsigned int numChannels;
    CUeglFrameType frameType;
    CUeglColorFormat eglColorFormat;
    CUarray_format cuFormat;
} CUeglFrame;

If resource is not registered then CUDA_ERROR_NOT_MAPPED is returned.

See also

cuGraphicsMapResources, cuGraphicsSubResourceGetMappedArray, cuGraphicsResourceGetMappedPointer, ::cudaGraphicsResourceGetMappedEglFrame

Parameters

eglFrame – - Returned eglFrame.
resource – - Registered resource to access.
index – - Index for cubemap surfaces.
mipLevel – - Mipmap level for the subresource to access.

Returns

CUDA_SUCCESS, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_INVALID_CONTEXT, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_INVALID_HANDLE, CUDA_ERROR_NOT_MAPPED