IMX6Q-Linux(QT)双屏同显

背景

Platform： IMX6Q
OS： Linux-QT5
Kernel: 4.1.15

需求

因项目需求，需要在imx6Q-Linux(QT)上实现双屏同显(LVDS+HDMI)
QT：5.8
LVDS(1280*800)
HDMI(此方法只支持1280*720，因为LVDS屏为1280*800，所以做720P不需要进行缩放或拉伸)

方法

修改DTS的HDMI对应的fb的配置
mode_str ="1280x720M@60";

修改fb的驱动(drivers/video/fbdev/mxc/mxc_ipuv3_fb.c)：

//mxcfb_set_par函数, 处理mxcfb_unmap_video_memory:
if(strcmp("DISP3 BG", fbi->fix.id) == 0){
	for (i = 0; i < num_registered_fb; i++) {
		if(strcmp("DISP4 BG", registered_fb[i]->fix.id) == 0)
		{
			break; 
		}
		//mxc_fbi = ((struct mxcfb_info *)(registered_fb[i]->par));

	}
	dev_info(fbi->device, "DISP3 BG map\n");
	fbi->screen_base = registered_fb[i]->screen_base;
	//fbi->fix = registered_fb[i]->fix;
	fbi->fix.smem_start = registered_fb[i]->fix.smem_start;
	fbi->var.yres = registered_fb[i]->var.yres;
	fbi->var.yres_virtual = registered_fb[i]->var.yres_virtual;
	fbi->fix.smem_len = registered_fb[i]->fix.smem_len;
	//fbi->var.yoffset = 80;
}
else{
	dev_info(fbi->device, "DISP4 BG map\n");
	if (!fbi->fix.smem_start || (mem_len > fbi->fix.smem_len)) {
		if (fbi->fix.smem_start)
			mxcfb_unmap_video_memory(fbi);

		if (mxcfb_map_video_memory(fbi) < 0)
			return -ENOMEM;
	}
}
/*zdd*/
/*
if (!fbi->fix.smem_start || (mem_len > fbi->fix.smem_len)) {
	
	if (fbi->fix.smem_start)
		mxcfb_unmap_video_memory(fbi);

	if (mxcfb_map_video_memory(fbi) < 0)
		return -ENOMEM;
}*/