树莓派所有的启动初始化都是在config.txt中完成的，因此，若插入HDMI树莓派没有显示桌面，则是没有配置HDMI。

首先在找到config.txt，两种方法：

第一种方法，将SD卡取出，用读卡器在windows上找到；

第二种方法，若登陆了树莓派直接在命令行搜索： sudo find / -name config.txt

可以看到位于/boot/config.txt中

找到该文件后，打开并按照如下修改：

uncomment相关注释：

hdmi_safe=1
overscan_left=16
overscan_right=16
overscan_top=16
overscan_bottom=16
hdmi_group=1
hdmi_mode=16
hdmi_drive=2

文件中对应的行如下：

# uncomment if you get no picture on HDMI for a default "safe" mode6 hdmi_safe=178 # uncomment this if your display has a black border of unused pixels visible9 # and your display can output without overscan10 #disable_overscan=11112 # uncomment the following to adjust overscan. Use positive numbers if console13 # goes off screen, and negative if there is too much border14 overscan_left=1615 overscan_right=1616 overscan_top=1617 overscan_bottom=161819 # uncomment to force a console size. By default it will be display's size minus20 # overscan.21 #framebuffer_width=128022 #framebuffer_height=7202324 # uncomment if hdmi display is not detected and composite is being output25 #hdmi_force_hotplug=12627 # uncomment to force a specific HDMI mode (this will force VGA)28 hdmi_group=129 hdmi_mode=163031 # uncomment to force a HDMI mode rather than DVI. This can make audio work in32 # DMT (computer monitor) modes33 hdmi_drive=2

其中，不同的mode，表明不同的分辨率，部分分辨率如下:

1. hdmi_mode = 1 VGA
2. hdmi_mode = 2 480p 60 Hz
3. hdmi_mode = 3 480p 60 Hz H
4. hdmi_mode = 4 720p 60 Hz
5. hdmi_mode = 5 1080i 60 Hz
6. hdmi_mode = 6 480i 60 Hz
7. hdmi_mode = 7 480i 60 Hz H
8. hdmi_mode = 8 240p 60 Hz
9. hdmi_mode = 9 240p 60 Hz H
10. hdmi_mode = 10 480i 60 Hz 4x
11. hdmi_mode = 11 480i 60 Hz 4x H.
12. hdmi_mode = 12 240p 60 Hz 4x
13. hdmi_mode = 13 240p 60 Hz 4x H.
14. hdmi_mode = 14 480p 60 Hz 2x
15. hdmi_mode = 15 480p 60 Hz 2x H.
16. hdmi_mode = 16 1080p 60 Hz
17. hdmi_mode = 17 576p 50 Hz
18. hdmi_mode = 18 576p 50 Hz H
19. hdmi_mode = 19 720p 50 Hz
20. hdmi_mode = 20 1080i 50 Hz
21. hdmi_mode = 21 576i 50 Hz
22. hdmi_mode = 22 576i 50 Hz H
23. hdmi_mode = 23 288p 50 Hz
24. hdmi_mode = 24 288p 50 Hz H
25. hdmi_mode = 25 576i 50 Hz 4x
26. hdmi_mode = 26 576i 50 Hz 4x H.
27. hdmi_mode = 27 288p 50 Hz 4x
28. hdmi_mode = 28 288p 50 Hz 4x H.
29. hdmi_mode = 29 576p 50 Hz 2x
30. hdmi_mode = 30 576p 50 Hz 2x H.
31. hdmi_mode = 31 1080p 50 Hz
32. hdmi_mode = 32 1080p 24 Hz
33. hdmi_mode = 33 1080p 25 Hz
34. hdmi_mode = 34 1080p 30 Hz
35. hdmi_mode = 35 480p 60 Hz 4x
36. hdmi_mode = 36 480p 60 Hz 4xH
37. hdmi_mode = 37 576p 50 Hz 4x
38. hdmi_mode = 38 576p 50 Hz 4x H.
39. hdmi_mode = 39 1080i 50 Hz减少消隐
40. hdmi_mode = 40 1080i 100 Hz
41. hdmi_mode = 41 720p 100 Hz
42. hdmi_mode = 42 576p 100 Hz
43. hdmi_mode = 43 576p 100 Hz H
44. hdmi_mode = 44 576i 100 Hz  
45. hdmi_mode = 45 576i 100 Hz H
46. hdmi_mode = 46 1080i 120 Hz  
47. hdmi_mode = 47 720p 120 Hz  
48. hdmi_mode = 48 480p 120 Hz  
49. hdmi_mode = 49 480p 120 Hz H
50. hdmi_mode = 50 480i 120 Hz  
51. hdmi_mode = 51 480i 120 Hz H
52. hdmi_mode = 52 576p 200 Hz  
53. hdmi_mode = 53 576p 200 Hz H
54. hdmi_mode = 54 576i 200 Hz  
55. hdmi_mode = 55 576i 200 Hz H
56. hdmi_mode = 56 480p 240 Hz  
57. hdmi_mode = 57 480p 240 Hz H
58. hdmi_mode = 58 480i 240 Hz  
59. hdmi_mode = 59 480i 240 Hz H

H表示16：9变体（通常为4：3模式）。

2x：像素加倍（即更高的时钟频率，每个像素重复两次）

4倍：像素翻了四倍（即更高的时钟频率，每个像素重复四次）