鼠标层该怎么使用？

各位大神，请问hi3520d的鼠标该怎么用呢，现在要实现功能是在鼠标层显示鼠标，我的代码如下
[code]/* 1. open framebuffer device overlay 0 */
    pstInfo->fd = open("/dev/fb3", O_RDWR, 0);
    if(pstInfo->fd < 0)
    {
        printf("open %s failed!\n",file);
        return HI_NULL;
    }

    bShow = HI_FALSE;
    if (ioctl(pstInfo->fd, FBIOPUT_SHOW_HIFB, &bShow) < 0)
    {
        printf("FBIOPUT_SHOW_HIFB failed!\n");
        return HI_NULL;
    }

    /* 2. set the screen original position */   
    stPoint.s32XPos = 150;
    stPoint.s32YPos = 150;

    if (ioctl(pstInfo->fd, FBIOPUT_SCREEN_ORIGIN_HIFB, &stPoint) < 0)
    {
        printf("set screen original show position failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }
#if 1
    /* 3.set alpha */
    stAlpha.bAlphaEnable = HI_FALSE;
    stAlpha.bAlphaChannel = HI_FALSE;
    stAlpha.u8Alpha0 = 0x0;
    stAlpha.u8Alpha1 = 0xff;
    stAlpha.u8GlobalAlpha = 0x80;
    if (ioctl(pstInfo->fd, FBIOPUT_ALPHA_HIFB,  &stAlpha) < 0)
    {
        printf("Set alpha failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }
#endif   

    /*all layer surport colorkey*/
    stColorKey.bKeyEnable = HI_TRUE;
    stColorKey.u32Key = 0x0;
    if (ioctl(pstInfo->fd, FBIOPUT_COLORKEY_HIFB, &stColorKey) < 0)
    {
        printf("FBIOPUT_COLORKEY_HIFB!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }

    /* 4. get the variable screen info */
    if (ioctl(pstInfo->fd, FBIOGET_VSCREENINFO, &var) < 0)
    {
        printf("Get variable screen info failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }

    /* 5. modify the variable screen info
          the screen size: IMAGE_WIDTH*IMAGE_HEIGHT
          the virtual screen size: VIR_SCREEN_WIDTH*VIR_SCREEN_HEIGHT
          (which equals to VIR_SCREEN_WIDTH*(IMAGE_HEIGHT*2))
          the pixel format: ARGB1555
    */
    usleep(4*1000*1000);
#if 1
    var.xres_virtual = 48;
    var.yres_virtual = 48;
    var.xres = 48;
    var.yres = 48;
#else
    var.xres_virtual = 1280;
    var.yres_virtual = 720*2;
    var.xres = 1280;
    var.yres = 720;
#endif

    var.transp= g_a16;
    var.red = g_r16;
    var.green = g_g16;
    var.blue = g_b16;
    var.bits_per_pixel = 16;
    var.activate = FB_ACTIVATE_NOW;
#if 1
    /* 6. set the variable screeninfo */
    if (ioctl(pstInfo->fd, FBIOPUT_VSCREENINFO, &var) < 0)
    {
        printf("Put variable screen info failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }
#endif
    /* 7. get the fix screen info */
    if (ioctl(pstInfo->fd, FBIOGET_FSCREENINFO, &fix) < 0)
    {
        printf("Get fix screen info failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }
    u32FixScreenStride = fix.line_length;   /*fix screen stride*/

    /* 8. map the physical video memory for user use */
    pShowScreen = mmap(HI_NULL, fix.smem_len, PROT_READ|PROT_WRITE, MAP_SHARED, pstInfo->fd, 0);
    if(MAP_FAILED == pShowScreen)
    {
        printf("mmap framebuffer failed!\n");
        close(pstInfo->fd);
        return HI_NULL;
    }[/code]

fb3对应鼠标层，可是在设置可变参数时候出错了，提示：Put variable screen info failed!

我的用法是不是不对，思路就是直接操作鼠标层的显存。