1 files changed, 81 insertions, 0 deletions
diff --git a/services/surfaceflinger/DisplayHardware/VSyncBarrier.cpp b/services/surfaceflinger/DisplayHardware/VSyncBarrier.cpp
new file mode 100644
index 0000000..187da20
--- /dev/null
+++ b/services/surfaceflinger/DisplayHardware/VSyncBarrier.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/fb.h>
+
+#include "DisplayHardware/VSyncBarrier.h"
+
+#ifndef FBIO_WAITFORVSYNC
+#define FBIO_WAITFORVSYNC   _IOW('F', 0x20, __u32)
+#endif
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+VSyncBarrier::VSyncBarrier() : mFd(-EINVAL) {
+#if HAS_WAITFORVSYNC
+    mFd = open("/dev/graphics/fb0", O_RDWR);
+    if (mFd < 0) {
+        mFd = -errno;
+    }
+    // try to see if FBIO_WAITFORVSYNC is supported
+    uint32_t crt = 0;
+    int err = ioctl(mFd, FBIO_WAITFORVSYNC, &crt);
+    if (err < 0) {
+        close(mFd);
+        mFd = -EINVAL;
+    }
+#endif
+}
+
+VSyncBarrier::~VSyncBarrier() {
+    if (mFd >= 0) {
+        close(mFd);
+    }
+}
+
+status_t VSyncBarrier::initCheck() const {
+    return mFd < 0 ? mFd : status_t(NO_ERROR);
+}
+
+// this must be thread-safe
+status_t VSyncBarrier::wait(nsecs_t* timestamp) const {
+    if (mFd < 0) {
+        return mFd;
+    }
+
+    int err;
+    uint32_t crt = 0;
+    do {
+        err = ioctl(mFd, FBIO_WAITFORVSYNC, &crt);
+    } while (err<0 && errno==EINTR);
+    if (err < 0) {
+        return -errno;
+    }
+    // ideally this would come from the driver
+    timestamp[0] = systemTime();
+    return NO_ERROR;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android