Add glFlush in surfaceflinger screenshot code.

After creating a syncKHR object with type EGL_SYNC_NATIVE_FENCE_ANDROID,
glFlush must be called before the EGL_SYNC_NATIVE_FENCE_FD_ANDROID attribute
is populated with a sync fd. We currently call eglDupNativeFenceFDANDROID
before issuing the flush.

Bug 18052459
Taken verbatim from matthew.k.gumbel@intel.com.

Change-Id: I3781d14f92862076e2bca7d27341a6dc6e7e3775

1 files changed, 2 insertions, 0 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 96a8adb..50968e7 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3201,6 +3201,8 @@ status_t SurfaceFlinger::captureScreenImplLocked(
                         EGLSyncKHR sync;
                         if (!DEBUG_SCREENSHOTS) {
                            sync = eglCreateSyncKHR(mEGLDisplay, EGL_SYNC_NATIVE_FENCE_ANDROID, NULL);
+                           // native fence fd will not be populated until flush() is done.
+                           getRenderEngine().flush();
                         } else {
                             sync = EGL_NO_SYNC_KHR;
                         }