Ensure we have a valid context for creating a decoder.

Author: elFarto

src/vabackend.c

@@ -1123,9 +1123,13 @@ static VAStatus nvCreateContext(
         //.vidLock             = drv->vidLock
     };
 
+    CHECK_CUDA_RESULT_RETURN(cu->cuCtxPushCurrent(drv->cudaContext), VA_STATUS_ERROR_OPERATION_FAILED);
+
     CUvideodecoder decoder;
     CHECK_CUDA_RESULT_RETURN(cv->cuvidCreateDecoder(&decoder, &vdci), VA_STATUS_ERROR_ALLOCATION_FAILED);
 
+    CHECK_CUDA_RESULT_RETURN(cu->cuCtxPopCurrent(NULL), VA_STATUS_ERROR_OPERATION_FAILED);
+
     Object contextObj = allocateObject(drv, OBJECT_TYPE_CONTEXT, sizeof(NVContext));
     LOG("Creating decoder: %p for context id: %d", decoder, contextObj->id);