Jacopo Mondi bc6440792b libcamera: Improve Request life cycle tracking
The current logging to track the status of a Request when running the
Android camera HAL provide the following information:

When a Request is queued to libcamera:
HAL camera_device.cpp:1776 '\_SB_.PCI0.I2C2.CAM0': Queueing Request to libcamera with 1 HAL streams

When a Request completes:
Request request.cpp:268 Request has completed - cookie: 138508601719648

The queueing of a Request reports the number of streams it contains
while the completion of a Request reports the address of the associated
cookie.

This makes very hard to keep track of what Requests have completed, as
the logging associated with a queue/complete event does not allow to identify
a Request easily.

Add two more printouts to make it easier to track a Request life cycle.
To make it possible to print the Request cookie in the CameraDevice
class add a method to access it from the CameraRequest class.

The result looks like the following trace:

Request request.cpp:92 Created request - cookie: 140701719392768
HAL camera_device.cpp:1710 '\_SB_.PCI0.I2C2.CAM0': Queueing request 140701719392768 with 1 streams
HAL camera_device.cpp:1747 '\_SB_.PCI0.I2C2.CAM0': 0 - (4160x3104)[0x00000023] -> (4160x3104)[NV12] (direct)
...
Request request.cpp:268 Request has completed - cookie: 140701719392768
HAL camera_device.cpp:1800 '\_SB_.PCI0.I2C2.CAM0': Request 140701719392768 completed with 1 streams..

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-02-02 18:50:03 +01:00
2020-10-27 14:48:17 +00:00

.. SPDX-License-Identifier: CC-BY-SA-4.0

.. section-begin-libcamera

===========
 libcamera
===========

**A complex camera support library for Linux, Android, and ChromeOS**

Cameras are complex devices that need heavy hardware image processing
operations. Control of the processing is based on advanced algorithms that must
run on a programmable processor. This has traditionally been implemented in a
dedicated MCU in the camera, but in embedded devices algorithms have been moved
to the main CPU to save cost. Blurring the boundary between camera devices and
Linux often left the user with no other option than a vendor-specific
closed-source solution.

To address this problem the Linux media community has very recently started
collaboration with the industry to develop a camera stack that will be
open-source-friendly while still protecting vendor core IP. libcamera was born
out of that collaboration and will offer modern camera support to Linux-based
systems, including traditional Linux distributions, ChromeOS and Android.

.. section-end-libcamera
.. section-begin-getting-started

Getting Started
---------------

To fetch the sources, build and install:

::

  git clone git://linuxtv.org/libcamera.git
  cd libcamera
  meson build
  ninja -C build install

Dependencies
~~~~~~~~~~~~

The following Debian/Ubuntu packages are required for building libcamera.
Other distributions may have differing package names:

A C++ toolchain: [required]
	Either {g++, clang}

Meson Build system: [required]
        meson (>= 0.51) ninja-build pkg-config

        If your distribution doesn't provide a recent enough version of meson,
        you can install or upgrade it using pip3.

        .. code::

            pip3 install --user meson
            pip3 install --user --upgrade meson

for the libcamera core: [required]
        python3-yaml python3-ply python3-jinja2

for IPA module signing: [required]
        libgnutls28-dev openssl

for the Raspberry Pi IPA: [optional]
        libboost-dev

        Support for Raspberry Pi can be disabled through the meson
         'pipelines' option to avoid this dependency.

for device hotplug enumeration: [optional]
	libudev-dev

for documentation: [optional]
	python3-sphinx doxygen graphviz

for gstreamer: [optional]
	libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev

for cam: [optional]
        libevent-dev

for qcam: [optional]
	qtbase5-dev libqt5core5a libqt5gui5 libqt5widgets5 qttools5-dev-tools libtiff-dev

for tracing with lttng: [optional]
        lttng-ust-dev python3-jinja2

Using GStreamer plugin
~~~~~~~~~~~~~~~~~~~~~~

To use GStreamer plugin from source tree, set the following environment so that
GStreamer can find it.

  export GST_PLUGIN_PATH=$(pwd)/build/src/gstreamer

The debugging tool `gst-launch-1.0` can be used to construct and pipeline and test
it. The following pipeline will stream from the camera named "Camera 1" onto the
default video display element on your system.

.. code::

  gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! videoconvert ! autovideosink

.. section-end-getting-started
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