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楼主 # 2022-11-29 17:02:57

SwordofMorning
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注册时间： 2022-05-20
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【lvgl疑问】程序无法读取event事件，evdev_read()未被调用

我尝试使用lvgl来实现一个图形界面的程序，现在UI可以显示在屏幕上，但是触摸屏没有反应。

我用的触摸芯片是GT911，我使用evtest或者ts_print都能读取到触摸屏的信息，但是lvgl应用却似乎没有调用evdev_read()。下面是我用evtest的输出：

No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0:	rk805 pwrkey
/dev/input/event1:	goodix-ts
/dev/input/event2:	adc-keys
/dev/input/event3:	Rmoncam A2 1080P: RMONCAM A2 10
Select the device event number [0-3]: 1
Input driver version is 1.0.1
Input device ID: bus 0x18 vendor 0xdead product 0xbeef version 0x28bb
Input device name: "goodix-ts"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 330 (BTN_TOUCH)
  Event type 3 (EV_ABS)
    Event code 48 (ABS_MT_TOUCH_MAJOR)
      Value      0
      Min        0
      Max      255
    Event code 50 (ABS_MT_WIDTH_MAJOR)
      Value      0
      Min        0
      Max      255
    Event code 53 (ABS_MT_POSITION_X)
      Value      0
      Min        0
      Max      800
    Event code 54 (ABS_MT_POSITION_Y)
      Value      0
      Min        0
      Max     1280
    Event code 57 (ABS_MT_TRACKING_ID)
      Value      0
      Min        0
      Max      255
Properties:
  Property type 1 (INPUT_PROP_DIRECT)
Testing ... (interrupt to exit)
Event: time 1501847472.953342, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1501847472.953342, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 195
Event: time 1501847472.953342, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 92
Event: time 1501847472.953342, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 26
Event: time 1501847472.953342, type 3 (EV_ABS), code 50 (ABS_MT_WIDTH_MAJOR), value 26
Event: time 1501847472.953342, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 0
Event: time 1501847472.953342, ++++++++++++++ SYN_MT_REPORT ++++++++++++
Event: time 1501847472.953342, -------------- SYN_REPORT ------------
Event: time 1501847472.964185, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 195
Event: time 1501847472.964185, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 92
Event: time 1501847472.964185, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 26
Event: time 1501847472.964185, type 3 (EV_ABS), code 50 (ABS_MT_WIDTH_MAJOR), value 26
Event: time 1501847472.964185, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 0
Event: time 1501847472.964185, ++++++++++++++ SYN_MT_REPORT ++++++++++++
Event: time 1501847472.964185, -------------- SYN_REPORT ------------
Event: time 1501847472.974098, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 195
Event: time 1501847472.974098, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 92
Event: time 1501847472.974098, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 26
Event: time 1501847472.974098, type 3 (EV_ABS), code 50 (ABS_MT_WIDTH_MAJOR), value 26
Event: time 1501847472.974098, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 0
Event: time 1501847472.974098, ++++++++++++++ SYN_MT_REPORT ++++++++++++
Event: time 1501847472.974098, -------------- SYN_REPORT ------------
Event: time 1501847472.984269, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 195
Event: time 1501847472.984269, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 92
Event: time 1501847472.984269, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 26
Event: time 1501847472.984269, type 3 (EV_ABS), code 50 (ABS_MT_WIDTH_MAJOR), value 26
Event: time 1501847472.984269, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 0
Event: time 1501847472.984269, ++++++++++++++ SYN_MT_REPORT ++++++++++++
Event: time 1501847472.984269, -------------- SYN_REPORT ------------
Event: time 1501847472.994804, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1501847472.994804, -------------- SYN_REPORT ------------

对于lvgl程序，我在lv_drv_conf.h中启用了如下内容：

#  define USE_EVDEV           1
#  define EVDEV_NAME   "/dev/input/event1"

下面是我的主函数，以及evdev_read()函数。

int main(void)
{

    // DRM_Init();

	// pthread_t pth_capt;

	// pthread_create(&pth_capt, NULL, (void*)V4L2_SP_Streaming, NULL);

#if 1
/* ================ */
/* ===== LVGL ===== */
/* ================ */

    /*LittlevGL init*/
    lv_init();

    /*Linux frame buffer device init*/
    drm_init();

    /*A small buffer for LittlevGL to draw the screen's content*/
    static lv_color_t buf[DISP_BUF_SIZE], buf1[DISP_BUF_SIZE];

    /*Initialize a descriptor for the buffer*/
    static lv_disp_draw_buf_t disp_buf;
    // lv_disp_draw_buf_init(&disp_buf, buf, NULL, DISP_BUF_SIZE);
    lv_disp_draw_buf_init(&disp_buf, buf, buf1, DISP_BUF_SIZE);

    /*Initialize and register a display driver*/
    static lv_disp_drv_t disp_drv;
    lv_disp_drv_init(&disp_drv);
    disp_drv.draw_buf   = &disp_buf;
    disp_drv.flush_cb   = drm_flush;
    disp_drv.hor_res    = 800;
    disp_drv.ver_res    = 1280;
    // disp_drv.screen_transp = 1;
    lv_disp_drv_register(&disp_drv);

#if 1
    // trans background
    lv_style_t style_scr_act;
    lv_style_init(&style_scr_act);
    lv_style_set_bg_opa(&style_scr_act, LV_OPA_TRANSP);
    lv_obj_add_style(lv_scr_act(), &style_scr_act, 0);
    // lv_disp_set_bg_opa(lv_scr_act(), LV_OPA_TRANSP);
#endif

#if 1
    evdev_init();
    static lv_indev_drv_t indev_drv_1;
    lv_indev_drv_init(&indev_drv_1); /*Basic initialization*/
    indev_drv_1.type = LV_INDEV_TYPE_POINTER;

    /*This function will be called periodically (by the library) to get the mouse position and state*/
    indev_drv_1.read_cb = evdev_read;
    lv_indev_t *mouse_indev = lv_indev_drv_register(&indev_drv_1);    
    // debug
    if (mouse_indev)
    {
        printf("register success.\n");
    }
    else
    {
        printf("register fail.\n");
    }
#endif

#if 1
    /*Set a cursor for the mouse*/
    LV_IMG_DECLARE(mouse_cursor_icon)
    lv_obj_t * cursor_obj = lv_img_create(lv_scr_act()); /*Create an image object for the cursor */
    lv_img_set_src(cursor_obj, &mouse_cursor_icon);           /*Set the image source*/
    lv_indev_set_cursor(mouse_indev, cursor_obj);             /*Connect the image  object to the driver*/
#endif
    
    mystart();
 
    printf("Start handler\n");

    /*Handle LitlevGL tasks (tickless mode)*/
    while(1) {
        lv_timer_handler();
        usleep(5000);
    }

#endif

    // pthread_exit(NULL);

    return 0;
}

void evdev_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
    struct input_event in;

    printf("[DEBUG] Entered evdev_read() function...\n");

    while(read(evdev_fd, &in, sizeof(struct input_event)) > 0) {
        if(in.type == EV_REL) {
            printf("[DEBUG] in.type == EV_REL\n");
            if(in.code == REL_X)
				#if EVDEV_SWAP_AXES
					evdev_root_y += in.value;
				#else
					evdev_root_x += in.value;
				#endif
            else if(in.code == REL_Y)
				#if EVDEV_SWAP_AXES
					evdev_root_x += in.value;
				#else
					evdev_root_y += in.value;
				#endif
        } else if(in.type == EV_ABS) {
            printf("[DEBUG] in.type == EV_ABS\n");
            if(in.code == ABS_X)
				#if EVDEV_SWAP_AXES
					evdev_root_y = in.value;
				#else
					evdev_root_x = in.value;
				#endif
            else if(in.code == ABS_Y)
				#if EVDEV_SWAP_AXES
					evdev_root_x = in.value;
				#else
					evdev_root_y = in.value;
				#endif
            else if(in.code == ABS_MT_POSITION_X)
                                #if EVDEV_SWAP_AXES
                                        evdev_root_y = in.value;
                                #else
                                        evdev_root_x = in.value;
                                #endif
            else if(in.code == ABS_MT_POSITION_Y)
                                #if EVDEV_SWAP_AXES
                                        evdev_root_x = in.value;
                                #else
                                        evdev_root_y = in.value;
                                #endif
            else if(in.code == ABS_MT_TRACKING_ID) {
                                if(in.value == -1)
                                    evdev_button = LV_INDEV_STATE_REL;
                                else if(in.value == 0)
                                    evdev_button = LV_INDEV_STATE_PR;
            }
        } else if(in.type == EV_KEY) {
            printf("[DEBUG] in.type == EV_KEY\n");
            if(in.code == BTN_MOUSE || in.code == BTN_TOUCH) {
                if(in.value == 0)
                    evdev_button = LV_INDEV_STATE_REL;
                else if(in.value == 1)
                    evdev_button = LV_INDEV_STATE_PR;
            } else if(drv->type == LV_INDEV_TYPE_KEYPAD) {
#if USE_XKB
                data->key = xkb_process_key(in.code, in.value != 0);
#else
                switch(in.code) {
                    case KEY_BACKSPACE:
                        data->key = LV_KEY_BACKSPACE;
                        break;
                    case KEY_ENTER:
                        data->key = LV_KEY_ENTER;
                        break;
                    case KEY_PREVIOUS:
                        data->key = LV_KEY_PREV;
                        break;
                    case KEY_NEXT:
                        data->key = LV_KEY_NEXT;
                        break;
                    case KEY_UP:
                        data->key = LV_KEY_UP;
                        break;
                    case KEY_LEFT:
                        data->key = LV_KEY_LEFT;
                        break;
                    case KEY_RIGHT:
                        data->key = LV_KEY_RIGHT;
                        break;
                    case KEY_DOWN:
                        data->key = LV_KEY_DOWN;
                        break;
                    case KEY_TAB:
                        data->key = LV_KEY_NEXT;
                        break;
                    default:
                        data->key = 0;
                        break;
                }
#endif /* USE_XKB */
                if (data->key != 0) {
                    /* Only record button state when actual output is produced to prevent widgets from refreshing */
                    data->state = (in.value) ? LV_INDEV_STATE_PR : LV_INDEV_STATE_REL;
                }
                evdev_key_val = data->key;
                evdev_button = data->state;
                return;
            }
        }
    }

    if(drv->type == LV_INDEV_TYPE_KEYPAD) {
        /* No data retrieved */
        data->key = evdev_key_val;
        data->state = evdev_button;
        return;
    }
    if(drv->type != LV_INDEV_TYPE_POINTER)
        return ;
    /*Store the collected data*/

#if EVDEV_CALIBRATE
    data->point.x = map(evdev_root_x, EVDEV_HOR_MIN, EVDEV_HOR_MAX, 0, drv->disp->driver->hor_res);
    data->point.y = map(evdev_root_y, EVDEV_VER_MIN, EVDEV_VER_MAX, 0, drv->disp->driver->ver_res);
#else
    data->point.x = evdev_root_x;
    data->point.y = evdev_root_y;
#endif

    // debug
    printf("[DEBUG] evdev_root_x: %d\n", evdev_root_x);
    printf("[DEBUG] evdev_root_y: %d\n", evdev_root_y);
    printf("[DEBUG] evdev_button: %d\n", evdev_button);

    data->state = evdev_button;

    if(data->point.x < 0)
      data->point.x = 0;
    if(data->point.y < 0)
      data->point.y = 0;
    if(data->point.x >= drv->disp->driver->hor_res)
      data->point.x = drv->disp->driver->hor_res - 1;
    if(data->point.y >= drv->disp->driver->ver_res)
      data->point.y = drv->disp->driver->ver_res - 1;

    printf("[DEBUG] Leaving evdev_read() function...\n");

    return ;
}

通过打印信息可以确定，程序进入了handler循环，并且没有挂掉。但是evdev_read()函数中的调试信息没有被打印，我尝试了触摸屏和鼠标，均不能使其被调用。我参考了github上的一个问题，该用户使用了/dev/input/touchscreen0替换/event2，并且解决了该问题。但是我这边只有如下的设备：

by-id  by-path	event0	event1	event2	event3	mice

我使用的kernel版本是4.19，lvgl版本为8.3。我不确定是否时程序对evdev的初始化出现了问题。

感谢您的回复。

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楼主 #1 2022-11-30 09:09:24

SwordofMorning
会员
注册时间： 2022-05-20
已发帖子： 6
积分： 11

Re: 【lvgl疑问】程序无法读取event事件，evdev_read()未被调用

我克隆了`lv_port_linux_frame_buffer`，并且重新配置了项目。问题已经解决。

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