Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) What:           /sys/.../uevent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) Date:           May 2017
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) KernelVersion:  4.13
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) Description:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)                 Enable passing additional variables for synthetic uevents that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)                 are generated by writing /sys/.../uevent file.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)                 Recognized extended format is::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 			ACTION [UUID [KEY=VALUE ...]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)                 The ACTION is compulsory - it is the name of the uevent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)                 action (``add``, ``change``, ``remove``). There is no change
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)                 compared to previous functionality here. The rest of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)                 extended format is optional.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)                 You need to pass UUID first before any KEY=VALUE pairs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)                 The UUID must be in ``xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)                 format where 'x' is a hex digit. The UUID is considered to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)                 a transaction identifier so it's possible to use the same UUID
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)                 value for one or more synthetic uevents in which case we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)                 logically group these uevents together for any userspace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)                 listeners. The UUID value appears in uevent as
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)                 ``SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`` environment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)                 variable.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)                 If UUID is not passed in, the generated synthetic uevent gains
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)                 ``SYNTH_UUID=0`` environment variable automatically.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)                 The KEY=VALUE pairs can contain alphanumeric characters only.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)                 It's possible to define zero or more pairs - each pair is then
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)                 delimited by a space character ' '. Each pair appears in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)                 synthetic uevent as ``SYNTH_ARG_KEY=VALUE``. That means the KEY
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)                 name gains ``SYNTH_ARG_`` prefix to avoid possible collisions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)                 with existing variables.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39)                 Example of valid sequence written to the uevent file::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)                     add fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed A=1 B=abc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)                 This generates synthetic uevent including these variables::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)                     ACTION=add
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)                     SYNTH_ARG_A=1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)                     SYNTH_ARG_B=abc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)                     SYNTH_UUID=fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) Users:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)                 udev, userspace tools generating synthetic uevents