WhyCan Forum(哇酷开发者社区)

直接gdb命令行呢
https://whycan.cn/t_1210.html#p5614

是这样的，我用imx283开发板，由于还没有移植好tslib，所以就用mouse_hid.c改了一下，在获取坐标的函数里直接赋坐标值模拟按键触摸，但是屏幕没有反应？

界面是自带的demo例程

bool mouse_hid_read(lv_indev_data_t * data)
{
    static lv_indev_state_t st;
    static unsigned char b;
    //ts_read(touch_pad,&sample,1);
    data->point.x = 240;
    data->point.y = 25;
    if(st == LV_INDEV_STATE_PR)
    {
        b ++;
        if(b > 20)
        {
            b = 0;
            st = LV_INDEV_STATE_REL;
        }
    }
    else
    {
        b ++;
        if(b > 20)
        {
            b = 0;
            st = LV_INDEV_STATE_PR;
        }
    }
    data->state = st;
    printf("x = %d y = %d state = %d\r\n",data->point.x,data->point.y,data->state);

    return false;
}

一开始以为是内核或者boot.scr的问题，后来发现每次插上串口都能一次性成功启动到登录界面
但是一旦拔了串口，就不行了，只停留在uboot的那一步，后面不动了。。
看了这篇博文后https://blog.csdn.net/guet_kite/article/details/78264740，说是串口的引脚受到干扰，以为是有按键输入。。。干扰怎么会有这么大的。。。，将信将疑，我把RX引脚接到地，再上电，有了！
各位坑有有木有谁也遇到过这种问题，你们是怎么解决的？

以前也遇到过这个问题 自己做的jlink 上的串口 没有上拉电阻  会一直往外面发0.
加上拉电阻：
1、让电路保持稳定的状态,避免误触发；
2、当有高频干扰信过来时,可以通过上拉对电源泄放掉；
3、很多口线和信号线是开漏输出,因此要加上拉,如IIC;(看全志的uboot源码，好像把gpio配置为上拉给注释了 你可以试试看)
4、为了阻抗匹配,多是信号完整性考虑.

https://www.ibm.com/developerworks/cn/linux/l-cairo/

#include <gtk/gtk.h>
#include <cairo.h>
#include <cairo-pdf.h>
#include <cairo-ps.h>
#include <cairo-svg.h>
#include <math.h>
#include <gdk/gdkkeysyms.h>
#include <string.h>



#define WIDTH  800
#define HEIGHT 600
#define STRIDE WIDTH*4
#define MAX_COORDS 1024



/* This path desribes what will be drawn later 
   The bulk of it is doing the IBM letters by connect the dots
   at the very end, we will get fancy and add a (R) Registered logo.
*/
static void
travel_path (cairo_t *cr)
{
   gint     pen_radius         = 10;

   cairo_set_source_rgb (cr, 1,1,1);
   cairo_paint (cr);

   cairo_set_line_width (cr, pen_radius*2);

   /* Use IBM Blue Pen Color with no ALPHA */
   cairo_set_source_rgba (cr, .3, .42, .69, 1);


   /* This Draws the IBM 8 Lines "I" Logo */
   cairo_move_to (cr, 10, 10);
   cairo_line_to (cr, 160, 10); 

   cairo_move_to (cr, 10, 40);
   cairo_line_to (cr, 160, 40);

   /* NOTE: Narrower Middle: 1/3 width */
   cairo_move_to (cr, 60, 70);
   cairo_line_to (cr, 110, 70);

   cairo_move_to (cr, 60, 100);
   cairo_line_to (cr, 110, 100);

   cairo_move_to (cr, 60, 130);
   cairo_line_to (cr, 110, 130);

   cairo_move_to (cr, 60, 160);
   cairo_line_to (cr, 110, 160);
   /* END Narrower Middle */

   cairo_move_to (cr, 10, 190);
   cairo_line_to (cr, 160, 190);

   cairo_move_to (cr, 10, 220);
   cairo_line_to (cr, 160, 220);
   /* END "I" DRAWING */




   /* This Draws the IBM 8 Lines "B" Logo */
   cairo_move_to (cr, 170, 10);
   cairo_line_to (cr, 340, 10); 

   cairo_move_to (cr, 170, 40);
   cairo_line_to (cr, 360, 40); 

   cairo_move_to (cr, 200, 70);
   cairo_line_to (cr, 250, 70);
   /*B's have holes in them! */
   cairo_move_to (cr, 300, 70); 
   cairo_line_to (cr, 360, 70); 


   cairo_move_to (cr, 210, 100);
   cairo_line_to (cr, 350, 100); 


   cairo_move_to (cr, 210, 130);
   cairo_line_to (cr, 350, 130); 


   cairo_move_to (cr, 200, 160);
   cairo_line_to (cr, 250, 160);
   /*B's have holes in them! */
   cairo_move_to (cr, 300, 160); 
   cairo_line_to (cr, 360, 160); 


   cairo_move_to (cr, 170, 190);
   cairo_line_to (cr, 360, 190); 


   cairo_move_to (cr, 170, 220);
   cairo_line_to (cr, 340, 220); 
   /* END "B" DRAWING */
	



   /* THE EVER POINTY "M"  */
   cairo_move_to (cr, 370, 10);
   cairo_line_to (cr, 470, 10); 
   cairo_move_to (cr, 560, 10);
   cairo_line_to (cr, 660, 10); 


   cairo_move_to (cr, 370, 40);
   cairo_line_to (cr, 490, 40); 
   cairo_move_to (cr, 540, 40);
   cairo_line_to (cr, 660, 40); 


   cairo_move_to (cr, 400, 70);
   cairo_line_to (cr, 510, 70); 
   cairo_move_to (cr, 520, 70);
   cairo_line_to (cr, 630, 70); 


   cairo_move_to (cr, 400, 100);
   cairo_line_to (cr, 630, 100); 


   cairo_move_to (cr, 400, 130);
   cairo_line_to (cr, 470, 130);
   cairo_move_to (cr, 480, 130);
   cairo_line_to (cr, 550, 130);
   cairo_move_to (cr, 560, 130);
   cairo_line_to (cr, 630, 130); 


   cairo_move_to (cr, 400, 160);
   cairo_line_to (cr, 470, 160);
   cairo_move_to (cr, 490, 160);
   cairo_line_to (cr, 540, 160);
   cairo_move_to (cr, 560, 160);
   cairo_line_to (cr, 630, 160); 


   cairo_move_to (cr, 370, 190);
   cairo_line_to (cr, 470, 190);
   cairo_move_to (cr, 500, 190);
   cairo_line_to (cr, 530, 190);
   cairo_move_to (cr, 560, 190);
   cairo_line_to (cr, 660, 190); 


   cairo_move_to (cr, 370, 220);
   cairo_line_to (cr, 470, 220);
   cairo_move_to (cr, 510, 220);
   cairo_line_to (cr, 520, 220);
   cairo_move_to (cr, 560, 220);
   cairo_line_to (cr, 660, 220); 
 
   /* END POINTY LETTERS */
   
   /* We stroke the path so we see everything we just specified
      by connecting the dots
   */
   cairo_stroke(cr);
 



   /* Let us add a disclaimer and show some fancy cairo: */
   /* We are going to want a nice fine lined circle around the R 
   you need to make sure you have stroked existing things
   that you wanted drawn with the larger pen before continuing. 
   */
   cairo_set_line_width (cr, pen_radius*.5);

   /* Now we will draw the fancy circle around the "R" */
   /* NOTE: The angles are in radians */
   cairo_move_to (cr, 710, 200);
   double angle1 = 0 * (M_PI/180.0);  
   double angle2 = 360 * (M_PI/180.0);

   /* We draw a large black circle */
   cairo_set_source_rgba (cr, 0, 0, 0, 1);
   cairo_arc (cr, 710, 200, 20, angle1, angle2);
   cairo_stroke (cr);

   /* We draw a smaller white circle centered on it */
   cairo_set_source_rgba (cr, 1, 1, 1, 1);
   cairo_arc (cr, 710, 200, 20, angle1, angle2);
   /* We use the fill operator to fill in the circle! */
   cairo_fill (cr);

   /* We are going to draw the letter "R" with black pen*/

   cairo_move_to (cr, 695,212); /* Bottom left of text at point */
   cairo_set_source_rgba (cr, 0, 0, 0, 1);
   cairo_select_font_face (cr, "Sans", CAIRO_FONT_SLANT_NORMAL,
                                       CAIRO_FONT_WEIGHT_BOLD);
   cairo_set_font_size (cr, 40);
   cairo_show_text (cr, "R");

    /* We stroke everything we have just done 
       to actually draw it...
    */ 
    cairo_stroke (cr);	 

}




/* Apply our path to the surface specified */
static void
draw (cairo_surface_t *surface)
{
    cairo_t *cr;
    cr = cairo_create (surface);

    /* Try applying the scale and rotate factors here to examine their effects on the output!*/
    /* cairo_rotate (cr, -M_PI / 4); */
    /* cairo_scale (cr, 2, 1.0);  */

    travel_path (cr);
    cairo_destroy (cr);
}


/* Function needed to draw to gtk window */
static void
draw_gtk (GtkWidget      *widget,
          GdkEventExpose *eev,
          gpointer        data)
{
  cairo_t *cr;
  cr = gdk_cairo_create (widget->window);
  travel_path (cr);
  cairo_destroy (cr);
}


/* We will draw our path on multiple surfaces to demonstrate 
   some of the various cairo backend
*/
int
main (gint    argc,
      gchar **argv)
{
    cairo_surface_t *surface;



    /* PDF Backend */
    surface = cairo_pdf_surface_create ("IBM.pdf",
					WIDTH, HEIGHT);
    draw (surface);
    cairo_surface_destroy (surface);


    /* Postscript Backend */
    surface = cairo_ps_surface_create ("IBM.ps",
					WIDTH, HEIGHT);
    draw (surface);
    cairo_surface_destroy (surface);


    /* Image backend */
    surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
					  WIDTH, HEIGHT);
    draw (surface);
    cairo_surface_write_to_png (surface, "IBM.png");
    cairo_surface_destroy (surface);


    /* Scalable Vector Graphics Backend */
    surface = cairo_svg_surface_create ("IBM.svg",
					WIDTH, HEIGHT);
    draw (surface);
    cairo_surface_destroy (surface);


    /* GTK Window using Cairo */
    gtk_init (NULL, NULL);        /* Fire up GTK!       */
    GtkWidget *mainwin;           /* Make a new windows */
    GtkWidget *canvas = NULL;     /* Make a new canvas  */
  
    mainwin = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    canvas = gtk_drawing_area_new ();
    gtk_widget_set_size_request (canvas, WIDTH, HEIGHT);     

    gtk_container_add (GTK_CONTAINER (mainwin), canvas); /* Place the canvas in the window */
 
    g_signal_connect (mainwin, "destroy", G_CALLBACK (gtk_main_quit), NULL); /* Quit graphically */

    /* Instead of drawing like usual, we connect the expose event to do the drawing! */
    g_signal_connect (G_OBJECT (canvas), "expose-event",
                      G_CALLBACK (draw_gtk), NULL);

    gtk_widget_show_all (mainwin); /* Show the window on the screen */
    gtk_main ();
    return 0;
}

编译指令:

gcc -o e e.c -I/usr/include/gtk-2.0/ -I/usr/include/glib-2.0/ -I/usr/lib/x86_64-linux-gnu/glib-2.0/include/ -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include/ -I/usr/include/gdk-pixbuf-2.0/ -I/usr/include/atk-1.0 -lgtk-x11-2.0 -lgdk-x11-2.0 -lgobject-2.0 -lrt -lglib-2.0 -pthread -lcairo

https://whycan.cn/files/members/3/QQ20180419110143.png

也可能是个特制的BROM

我用短接CS到地的方法很管用，就是不方便。不知底板是否能方便点

另外@kgp0213兄，是否试过xboot自带的guidemo，是否卡顿?它那个实现用的cairo画图库应该开销更大

daydayup 说：

目前还不支持tf卡启动，确实需要得自己改，难度不小。

请教uboot的实现原理是什么？修改xboot的难点在哪里？

没有解决， 5刀就这样活生生 被 hostmybytes.com 这个垃圾黑了，
这种服务态度，就等着被中国秒杀吧.

柳暗花明又一村，终于找到解决方案了: https://github.com/skeeto/opengl-demo

如果您的GPU不支持OpenGL 3.3并且您使用Mesa 10.0+，则可以使用环境变量强制渲染软件 LIBGL_ALWAYS_SOFTWARE=1。

把环境变量强制加上，终于搞定这个棘手的问题:

yunge@ubuntu:/tmp/nuklear/example/bin$ LIBGL_ALWAYS_SOFTWARE=1 ./extended
piemenu selected: 4
pushed!
piemenu selected: 4
piemenu selected: 4
piemenu selected: 4

有图有真相:
https://whycan.cn/files/members/3/QQ20180218185909.png