BufferQueue: Add allocateBuffers method

This adds an allocateBuffers method to BufferQueue, which instructs
it to allocate up to the maximum number of buffers allowed by the
current configuration. The goal is that this method can be called
ahead of render time, which will prevent dequeueBuffers from blocking
in allocation and inducing jank.

This interface is also plumbed up to the native Surface (and, in
another change, up to the Java Surface and ThreadedRenderer).

Bug: 11792166
Change-Id: I4aa96b4351ea1c95ed5db228ca3ef98303229c74

1 files changed, 7 insertions, 0 deletions

diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 88c45b2..8cb9189 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -91,6 +91,13 @@ void Surface::setSidebandStream(const sp<NativeHandle>& stream) {
     mGraphicBufferProducer->setSidebandStream(stream);
 }
 
+void Surface::allocateBuffers() {
+    uint32_t reqWidth = mReqWidth ? mReqWidth : mUserWidth;
+    uint32_t reqHeight = mReqHeight ? mReqHeight : mUserHeight;
+    mGraphicBufferProducer->allocateBuffers(mSwapIntervalZero, mReqWidth,
+            mReqHeight, mReqFormat, mReqUsage);
+}
+
 int Surface::hook_setSwapInterval(ANativeWindow* window, int interval) {
     Surface* c = getSelf(window);
     return c->setSwapInterval(interval);