V4L2VEA: fix keyframe is not generated on nyan

content/common/gpu/media/v4l2_video_encode_accelerator.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <string.h>
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
@@ skipping 342 matching lines @@
 
   if (force_keyframe) {
     // TODO(posciak): this presently makes for slightly imprecise encoding
     // parameters updates.  To precisely align the parameter updates with the
     // incoming input frame, we should queue the parameters together with the
     // frame onto encoder_input_queue_ and apply them when the input is about
     // to be queued to the codec.
     std::vector<struct v4l2_ext_control> ctrls;
     struct v4l2_ext_control ctrl;
     memset(&ctrl, 0, sizeof(ctrl));
-    ctrl.id = V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME;
+    // Nyan still uses the old control and it reports success for unknown
+    // controls. Try the old control first.
+    // TODO(wuchengli): remove this after http://crosbug.com/p/53598 is fixed.
+    ctrl.id = V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE;
+    ctrl.value = V4L2_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE_I_FRAME;
     ctrls.push_back(ctrl);
     if (!SetExtCtrls(ctrls)) {
-      // Some platforms still use the old control. Fallback before they are
-      // updated.
       ctrls.clear();
       memset(&ctrl, 0, sizeof(ctrl));
-      ctrl.id = V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE;
-      ctrl.value = V4L2_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE_I_FRAME;
+      ctrl.id = V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME;
       ctrls.push_back(ctrl);
       if (!SetExtCtrls(ctrls)) {
         LOG(ERROR) << "Failed requesting keyframe";
         NOTIFY_ERROR(kPlatformFailureError);
         return;
       }
     }
   }
 }
 
@@ skipping 801 matching lines @@
   reqbufs.count = 0;
   reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
   reqbufs.memory = V4L2_MEMORY_MMAP;
   IOCTL_OR_LOG_ERROR(VIDIOC_REQBUFS, &reqbufs);
 
   output_buffer_map_.clear();
   free_output_buffers_.clear();
 }
 
 }  // namespace content