让 Xorg 识别 libevdev 虚拟设备答案

【问题标题】：Make Xorg recognize libevdev virtual device让 Xorg 识别 libevdev 虚拟设备
【发布时间】：2020-10-28 01:19:02
【问题描述】：

我一直在尝试使用 libevdev 创建一个简单的程序来创建一个虚拟设备，该设备将每秒将鼠标在 X 轴上移动 50 个点。程序运行正常，但是 Xorg 无法识别新创建的虚拟设备。

我想这将是一件微不足道的事情，但我不知道是什么。

Xorgs 的日志说：

[  5860.310] (II) config/udev: Adding input device test device Mouse (/dev/input/event18)
[  5860.310] (II) No input driver specified, ignoring this device.
[  5860.310] (II) This device may have been added with another device file.

程序：

#include <libevdev/libevdev.h>
#include <libevdev/libevdev-uinput.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

static void check(int i) {
    if (i < 0) {        
        printf("%s\n", strerror(-i));
        exit(1);
    }
}

int main() {
    struct libevdev* evdev = libevdev_new();
    libevdev_set_name(evdev, "test device Mouse");
    libevdev_set_id_vendor(evdev, 0x1);
    libevdev_set_id_product(evdev, 0x1);
    libevdev_set_id_version(evdev, 0x1);
    libevdev_set_id_bustype(evdev, BUS_USB);

    check(libevdev_enable_event_type(evdev, EV_REL));
    check(libevdev_enable_event_code(evdev, EV_REL, REL_X, NULL));
    check(libevdev_enable_event_code(evdev, EV_REL, REL_Y, NULL));
    check(libevdev_enable_event_code(evdev, EV_SYN, SYN_REPORT, NULL));

    struct libevdev_uinput* uinput;
    check(libevdev_uinput_create_from_device(evdev, LIBEVDEV_UINPUT_OPEN_MANAGED, &uinput));

    for (int i = 0; i < 1000; i++) {
        check(libevdev_uinput_write_event(uinput, EV_REL, REL_X, 50));
        check(libevdev_uinput_write_event(uinput, EV_SYN, SYN_REPORT, 0));

        sleep(1);
    }
}

我做错了什么？

【问题讨论】：

标签： c input mouse xorg uinput

【解决方案1】：

问题是需要启用鼠标按钮才能使鼠标移动起作用。

添加这些行可以解决问题：

check(libevdev_enable_event_type(evdev, EV_KEY));
check(libevdev_enable_event_code(evdev, EV_KEY, BTN_LEFT, NULL));
check(libevdev_enable_event_code(evdev, EV_KEY, BTN_RIGHT, NULL));

【讨论】：