DISCONTINUATION OF PROJECT

This project will no longer be maintained by Intel.
Intel has ceased development and contributions including, but not limited to, maintenance, bug fixes, new releases, or updates, to this project.
Intel no longer accepts patches to this project.
If you have an ongoing need to use this project, are interested in independently developing it, or would like to maintain patches for the open source software community, please create your own fork of this project.

HID USI BPF tools

This repository contains BPF tools for HID USI. Two programs are built out of this repository: a client program (hid_usi_client), and a server (hid_usi_server) containing a BPF kernel object.

Kernel config

Kernel to be used must contain the following BPF config:

CONFIG_BPF_SYSCALL=y
CONFIG_BPF_JIT=y
CONFIG_BPF_JIT_DEFAULT_ON=y
CONFIG_KALLSYMS_ALL=y
CONFIG_DEBUG_INFO=y
CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
CONFIG_DEBUG_INFO_BTF=y
CONFIG_PAHOLE_HAS_SPLIT_BTF=y
CONFIG_DEBUG_INFO_BTF_MODULES=y
CONFIG_GDB_SCRIPTS=y
CONFIG_BPF_EVENTS=y

Building

To build deps + BPF tools, enter src/ directory and:

make KERNEL_SRC=<kernel-dir> deps
make KERNEL_SRC=<kernel-dir> all

If everything passes correctly, output images should be available at the source directory.

Kernel BPF program

Kernel BPF program is built out of hid_usi_server_kern.c, and it is built-in to the hid_usi_server. The BPF program is automatically started once the server is started.

Server program

Server program is called hid_usi_server and it will load the BPF program to kernel, and create a D-BUS server over which it can be used to program the pen parameters. Server source is at hid_usi_server.c. To launch the server program, run

hid_usi_server 0

This will attach the server to hidraw0 device and load the common BPF object. Server will also create a D-BUS service over system bus for the client to attach to.

Client program

Client program can be used to tell the server to program pen parameters. Client source is at hid_usi_client.c. To launch the client program, simply do:

hid_usi_client

It will automatically connect to the server and will show the help text. E.g. to dump current parameters, run:

hid_usi_client --dump

Pen parameters can also be modified, e.g.

hid_usi_client --color 3

... will change the pen color to 3.