[Beignet] [PATCH V2 2/3] enable CL_DEVICE_HOST_UNIFIED_MEMORY when userptr is supported

[Guo Yejun]

userptr is firstly checked at compile time with libdrm version, but
it does not ensure the system has such capability (for exmaple, with
old linux kernel), so also take a check at run time for the device info.

V2: add runtime check to see if userptr is really supported
Signed-off-by: Guo Yejun <yejun.guo at intel.com>
---
 src/cl_device_id.c | 18 ++++++++++++++++++
 src/cl_gt_device.h |  4 ++++
 2 files changed, 22 insertions(+)

diff --git a/src/cl_device_id.c b/src/cl_device_id.c
index c911c23..8ab1651 100644
--- a/src/cl_device_id.c
+++ b/src/cl_device_id.c
@@ -36,6 +36,8 @@
 #define CL_DEVICE_BUILT_IN_KERNELS 0x103F
 #endif
 
+void *aligned_alloc(size_t alignment, size_t size);
+
 static struct _cl_device_id intel_ivb_gt2_device = {
   INIT_ICD(dispatch)
   .max_compute_unit = 16,
@@ -401,6 +403,22 @@ brw_gt3_break:
     }
   }
 
+#ifdef HAS_USERPTR
+  cl_driver dummy = cl_driver_new(NULL);
+  cl_buffer_mgr bufmgr = cl_driver_get_bufmgr(dummy);
+
+  const size_t sz = 4096;
+  char* host_ptr = (char*)aligned_alloc(4096, sz);
+  cl_buffer bo = cl_buffer_alloc_userptr(bufmgr, "CL memory object", host_ptr, sz, 0);
+  if (bo == NULL)
+    ret->host_unified_memory = CL_FALSE;
+  else
+    cl_buffer_unreference(bo);
+
+  free(host_ptr);
+  cl_driver_delete(dummy);
+#endif
+
   return ret;
 }
 
diff --git a/src/cl_gt_device.h b/src/cl_gt_device.h
index 3cd54eb..c9caa1d 100644
--- a/src/cl_gt_device.h
+++ b/src/cl_gt_device.h
@@ -60,7 +60,11 @@
 .max_constant_buffer_size = 512 << 10,
 .max_constant_args = 8,
 .error_correction_support = CL_FALSE,
+#ifdef HAS_USERPTR
+.host_unified_memory = CL_TRUE,
+#else
 .host_unified_memory = CL_FALSE,
+#endif
 .profiling_timer_resolution = 80, /* ns */
 .endian_little = CL_TRUE,
 .available = CL_TRUE,
-- 
2.1.0