Add tracepoints to v4l2reader for ftrace
This makes it easier to trace what is happening in the kernel.
Change-Id: Ie016f1a0bfdfd52cf143bdf1d754ebd366992392
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/vision/v4l2_reader.cc b/frc971/vision/v4l2_reader.cc
index d46e7b5..f3640db 100644
--- a/frc971/vision/v4l2_reader.cc
+++ b/frc971/vision/v4l2_reader.cc
@@ -99,23 +99,28 @@
EnqueueBuffer(saved_buffer_.index);
saved_buffer_.Clear();
}
+ ftrace_.FormatMessage("Enqueued previous buffer %d", saved_buffer_.index);
while (true) {
const BufferInfo previous_buffer = saved_buffer_;
saved_buffer_ = DequeueBuffer();
+ ftrace_.FormatMessage("Dequeued %d", saved_buffer_.index);
if (saved_buffer_) {
// We got a new buffer. Return the previous one (if relevant) and keep
// going.
if (previous_buffer) {
+ ftrace_.FormatMessage("Previous %d", previous_buffer.index);
EnqueueBuffer(previous_buffer.index);
}
continue;
}
if (!previous_buffer) {
// There were no images to read. Return an indication of that.
+ ftrace_.FormatMessage("No images to read");
return false;
}
// We didn't get a new one, but we already got one in a previous
// iteration, which means we found an image so return it.
+ ftrace_.FormatMessage("Got saved buffer %d", saved_buffer_.index);
saved_buffer_ = previous_buffer;
buffers_[saved_buffer_.index].PrepareMessage(rows_, cols_, ImageSize(),
saved_buffer_.monotonic_eof);