surface: add support for dma_buf exports.

Use the new VA buffer export APIs to allow for a VA surface to be
exposed as a plain PRIME fd. This is in view to simplifying interop
with EGL or OpenCL for instance.

https://bugzilla.gnome.org/show_bug.cgi?id=735364

gst-libs/gst/vaapi/Makefile.am

@@ -69,6 +69,7 @@ libgstvaapi_source_c =				\
 	gstvaapiprofile.c			\
 	gstvaapisubpicture.c			\
 	gstvaapisurface.c			\
+	gstvaapisurface_drm.c			\
 	gstvaapisurfacepool.c			\
 	gstvaapisurfaceproxy.c			\
 	gstvaapitexture.c			\
@@ -98,6 +99,7 @@ libgstvaapi_source_h =				\
 	gstvaapiprofile.h			\
 	gstvaapisubpicture.h			\
 	gstvaapisurface.h			\
+	gstvaapisurface_drm.h			\
 	gstvaapisurfacepool.h			\
 	gstvaapisurfaceproxy.h			\
 	gstvaapitexture.h			\

gst-libs/gst/vaapi/gstvaapibufferproxy.c

@@ -21,6 +21,8 @@
  */
 
 #include "sysdeps.h"
+#include <va/va_drmcommon.h>
+#include "gstvaapicompat.h"
 #include "gstvaapibufferproxy.h"
 #include "gstvaapibufferproxy_priv.h"
 #include "gstvaapiutils.h"
@@ -40,6 +42,9 @@ from_GstVaapiBufferMemoryType (guint type)
   guint va_type;
 
   switch (type) {
+    case GST_VAAPI_BUFFER_MEMORY_TYPE_DMA_BUF:
+      va_type = VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME;
+      break;
     default:
       va_type = 0;
       break;
@@ -53,6 +58,9 @@ to_GstVaapiBufferMemoryType (guint va_type)
   guint type;
 
   switch (va_type) {
+    case VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME:
+      type = GST_VAAPI_BUFFER_MEMORY_TYPE_DMA_BUF;
+      break;
     default:
       type = 0;
       break;

gst-libs/gst/vaapi/gstvaapibufferproxy.h

@@ -57,6 +57,16 @@ G_BEGIN_DECLS
 
 typedef struct _GstVaapiBufferProxy             GstVaapiBufferProxy;
 
+/**
+ * GstVaapiBufferMemoryType:
+ * @GST_VAAPI_BUFFER_MEMORY_TYPE_DMA_BUF: DRM PRIME buffer memory type.
+ *
+ * Set of underlying VA buffer memory types.
+ */
+typedef enum {
+  GST_VAAPI_BUFFER_MEMORY_TYPE_DMA_BUF = 1,
+} GstVaapiBufferMemoryType;
+
 GstVaapiBufferProxy *
 gst_vaapi_buffer_proxy_new (guintptr handle, guint type, gsize size,
     GDestroyNotify destroy_func, gpointer user_data);

gst-libs/gst/vaapi/gstvaapisurface_drm.c

@@ -0,0 +1,77 @@
+/*
+ *  gstvaapisurface_drm.c - VA surface abstraction (DRM interop)
+ *
+ *  Copyright (C) 2014 Intel Corporation
+ *    Author: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public License
+ *  as published by the Free Software Foundation; either version 2.1
+ *  of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA 02110-1301 USA
+ */
+
+#include "sysdeps.h"
+#include "gstvaapisurface_drm.h"
+#include "gstvaapisurface_priv.h"
+#include "gstvaapiimage_priv.h"
+#include "gstvaapibufferproxy_priv.h"
+
+static GstVaapiBufferProxy *
+gst_vaapi_surface_get_drm_buf_handle (GstVaapiSurface * surface, guint type)
+{
+  GstVaapiBufferProxy *proxy;
+  GstVaapiImage *image;
+
+  image = gst_vaapi_surface_derive_image (surface);
+  if (!image)
+    goto error_derive_image;
+
+  proxy =
+      gst_vaapi_buffer_proxy_new_from_object (GST_VAAPI_OBJECT (surface),
+      image->internal_image.buf, type, gst_vaapi_object_unref, image);
+  if (!proxy)
+    goto error_alloc_export_buffer;
+  return proxy;
+
+  /* ERRORS */
+error_derive_image:
+  GST_ERROR ("failed to extract image handle from surface");
+  return NULL;
+error_alloc_export_buffer:
+  GST_ERROR ("failed to allocate export buffer proxy");
+  gst_vaapi_object_unref (image);
+  return NULL;
+}
+
+/**
+ * gst_vaapi_surface_get_dma_buf_handle:
+ * @surface: a #GstVaapiSurface
+ *
+ * If the underlying VA driver implementation supports it, this
+ * function allows for returning a suitable dma_buf (DRM) buffer
+ * handle as a #GstVaapiBufferProxy instance. The resulting buffer
+ * handle is live until the last reference to the proxy gets
+ * released. Besides, any further change to the parent VA @surface may
+ * fail.
+ *
+ * Return value: the underlying buffer as a #GstVaapiBufferProxy
+ * instance.
+ */
+GstVaapiBufferProxy *
+gst_vaapi_surface_get_dma_buf_handle (GstVaapiSurface * surface)
+{
+  g_return_val_if_fail (surface != NULL, NULL);
+
+  return gst_vaapi_surface_get_drm_buf_handle (surface,
+      GST_VAAPI_BUFFER_MEMORY_TYPE_DMA_BUF);
+}

gst-libs/gst/vaapi/gstvaapisurface_drm.h

@@ -0,0 +1,36 @@
+/*
+ *  gstvaapisurface_drm.h - VA surface abstraction (DRM interop)
+ *
+ *  Copyright (C) 2014 Intel Corporation
+ *    Author: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public License
+ *  as published by the Free Software Foundation; either version 2.1
+ *  of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA 02110-1301 USA
+ */
+
+#ifndef GST_VAAPI_SURFACE_DRM_H
+#define GST_VAAPI_SURFACE_DRM_H
+
+#include <gst/vaapi/gstvaapisurface.h>
+#include <gst/vaapi/gstvaapibufferproxy.h>
+
+G_BEGIN_DECLS
+
+GstVaapiBufferProxy *
+gst_vaapi_surface_get_dma_buf_handle (GstVaapiSurface * surface);
+
+G_END_DECLS
+
+#endif /* GST_VAAPI_SURFACE_DRM_H */