04b20723d4
Some media devices, such as V4L2 M2M devices, share the same device node for multiple entities. The udev enumerator used to support this, but commit6e62034900("libcamera: device_enumerator: fix udev media graph loading dependency") broke this. To fix the problem, rework the media device to V4L2 devices matching code. A new MediaDeviceDeps internal struct stores unmet device number dependencies for a media device, and is stored in a list of pending media devices. To avoid linear lookups, the dependencies are cached in a reverse map of device number to media device dependencies. Fixes:6e62034900("libcamera: device_enumerator: fix udev media graph loading dependency") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
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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.
Getting Started
---------------
To build and install:
::
meson build
cd build
ninja
ninja 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}
for libcamera: [required]
meson ninja-build
for device hotplug enumeration: [optional]
pkg-config libudev-dev
for qcam: [optional]
qtbase5-dev libqt5core5a libqt5gui5 libqt5widgets5
for documentation: [optional]
python3-sphinx doxygen