display: add support for DRM Render-Nodes.

Add support for DRM Render-Nodes. This is a new feature that appeared
in kernel 3.12 for experimentation purposes, but was later declared
stable enough in kernel 3.15 for getting enabled by default.

This allows headless usages without authentication at all, i.e. usages
through plain ssh connections is possible.

diff --git a/gst-libs/gst/vaapi/gstvaapidisplay_drm.c b/gst-libs/gst/vaapi/gstvaapidisplay_drm.c
index 9114bfc47874c3389d1d80ad2c7400c99dad9d4f..be748b9f0da7e2a69adffbabf666634064742e60 100644 (file)
--- a/gst-libs/gst/vaapi/gstvaapidisplay_drm.c
+++ b/gst-libs/gst/vaapi/gstvaapidisplay_drm.c
@@ -42,6 +42,15 @@
 
 static const guint g_display_types = 1U << GST_VAAPI_DISPLAY_TYPE_DRM;
 
+typedef enum
+{
+  DRM_DEVICE_LEGACY = 1,
+  DRM_DEVICE_RENDERNODES,
+} DRMDeviceType;
+
+static DRMDeviceType g_drm_device_type;
+static GMutex g_drm_device_type_lock;
+
 /* Get default device path. Actually, the first match in the DRM subsystem */
 static const gchar *
 get_default_device_path (GstVaapiDisplay * display)
@@ -65,6 +74,17 @@ get_default_device_path (GstVaapiDisplay * display)
       goto end;
 
     udev_enumerate_add_match_subsystem (e, "drm");
+    switch (g_drm_device_type) {
+      case DRM_DEVICE_LEGACY:
+        udev_enumerate_add_match_sysname (e, "card[0-9]*");
+        break;
+      case DRM_DEVICE_RENDERNODES:
+        udev_enumerate_add_match_sysname (e, "renderD[0-9]*");
+        break;
+      default:
+        GST_ERROR ("unknown drm device type (%d)", g_drm_device_type);
+        goto end;
+    }
     udev_enumerate_scan_devices (e);
     udev_list_entry_foreach (l, udev_enumerate_get_list_entry (e)) {
       syspath = udev_list_entry_get_name (l);
@@ -176,7 +196,8 @@ set_device_path_from_fd (GstVaapiDisplay * display, gint drm_device)
     path_length = strlen (path);
     if (str + busid_length >= path + path_length)
       continue;
-    if (strncmp (&str[busid_length], "/drm/card", 9) != 0)
+    if (strncmp (&str[busid_length], "/drm/card", 9) != 0 &&
+        strncmp (&str[busid_length], "/drm/renderD", 12) != 0)
       continue;
 
     device = udev_device_new_from_syspath (udev, path);
@@ -348,8 +369,28 @@ gst_vaapi_display_drm_class (void)
 GstVaapiDisplay *
 gst_vaapi_display_drm_new (const gchar * device_path)
 {
-  return gst_vaapi_display_new (gst_vaapi_display_drm_class (),
-      GST_VAAPI_DISPLAY_INIT_FROM_DISPLAY_NAME, (gpointer) device_path);
+  GstVaapiDisplay *display;
+  guint types[2], i, num_types = 0;
+
+  if (device_path)
+    types[num_types++] = 0;
+  else if (g_drm_device_type)
+    types[num_types++] = g_drm_device_type;
+  else {
+    types[num_types++] = DRM_DEVICE_RENDERNODES;
+    types[num_types++] = DRM_DEVICE_LEGACY;
+  }
+
+  g_mutex_lock (&g_drm_device_type_lock);
+  for (i = 0; i < num_types; i++) {
+    g_drm_device_type = types[i];
+    display = gst_vaapi_display_new (gst_vaapi_display_drm_class (),
+        GST_VAAPI_DISPLAY_INIT_FROM_DISPLAY_NAME, (gpointer) device_path);
+    if (display || device_path)
+      break;
+  }
+  g_mutex_unlock (&g_drm_device_type_lock);
+  return display;
 }
 
 /**