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04f19d6735
Add persistent symlinks for media controller ("mediaX") devices, based
on their ID_PATH udev properties.
For example, if the uvcvideo driver creates /dev/media0, a persistent
name may be:
/dev/media/by-path/pci-0000:04:00.3-usb-0:1:1.0-media-controller
Persistent links are a handy tool to make scripts self-documenting
during development or in tests, as well as less error prone in case of
devices changing enumeration order. For media controllers, one can
alternatively scan through all of them and look for a matching bus_info
in their struct media_device_info, but the links are much handier when
drafting something by hand.
A similar pattern already exists for Video4Linux /dev/videoX devices,
see 60-persistent-v4l.rules for those.
Files in this directory contain configuration for systemd-udevd.service, a daemon that manages symlinks to device nodes, permissions of devices nodes, emits device events for userspace, and renames network interfaces. See man:udev(7) for an overview of the configuration file format, and man:systemd-udevd.service(8) for a description of service itself. Use 'systemd-analyze cat-config udev/rules.d' to display the effective config.