Detect if we are able to init cuDNN handle before auto enable it.

theano/gof/cmodule.py

@@ -1851,7 +1851,8 @@ class GCC_compiler(object):
             return (compilation_ok, run_ok, out, err)
 
     @staticmethod
-    def try_flags(flag_list, preambule="", try_run=False, output=False):
+    def try_flags(flag_list, preambule="", body="",
+                  try_run=False, output=False):
         '''
         Try to compile a dummy file with these flags.
 
@@ -1865,6 +1866,7 @@ class GCC_compiler(object):
         %(preambule)s
         int main(int argc, char** argv)
         {
+            %(body)s
             return 0;
         }
         """ % locals())

theano/sandbox/cuda/dnn.py

@@ -25,8 +25,26 @@ def dnn_available():
             dnn_available.msg = "Device not supported by cuDNN"
             dnn_available.avail = False
         else:
+            preambule = """
+#include <cudnn.h>
+#include <stdio.h>
+#include <cuda.h>
+#include <cudnn_helper.h>
+            """
+
+            body = """
+cudnnHandle_t _handle = NULL;
+cudnnStatus_t err;
+if ((err = cudnnCreate(&_handle)) != CUDNN_STATUS_SUCCESS) {
+  fprintf(stderr, "could not create cuDNN handle: %s",
+          cudnnGetErrorString(err));
+  return 1;
+}
+"""
+
             comp, run, out, err = gof.cmodule.GCC_compiler.try_flags(
-                ["-l", "cudnn"], preambule="#include <cudnn.h>",
+                ["-l", "cudnn", "-I" + os.path.dirname(__file__)],
+                preambule=preambule, body=body,
                 try_run=True, output=True)
 
             dnn_available.avail = comp and run
@@ -90,7 +108,7 @@ cudnnHandle_t _handle = NULL;
         return ["""{
 cudnnStatus_t err;
 if ((err = cudnnCreate(&_handle)) != CUDNN_STATUS_SUCCESS) {
-  PyErr_Format(PyExc_RuntimeError, "could not create cudnn handle: %%s",
+  PyErr_Format(PyExc_RuntimeError, "could not create cuDNN handle: %%s",
                cudnnGetErrorString(err));
   return %s;
 }