As a follow-up in the style of:
873be895ed ("udev: add USB revision in ID_PATH")
this patch adds a second symlink for media controllers, this time
including the USB revision.
This means that in addition to persistent symlinks like:
pci-0000:04:00.3-usb-0:1:1.0-media-controller -> ../../media0
We now also get:
pci-0000:04:00.3-usbv2-0:1:1.0-media-controller -> ../../media0
...which helps distinguish media devices plugged into different USB root
hubs provided by the same PCI card, at least as long as they are for
different USB revisions.
Fixes: 04f19d6735 ("udev: Add /dev/media/by-path symlinks for media controllers")
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.
