1.开机按esc进入ubuntu高级选项，选择内核版本，之后回车

注意：记住此版本号

2.接下来按照如下操作

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

# GRUB_DEFAULT=0
GRUB_DEFAULT="1> 2"  # 修改后的配置
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

3.重启之后采用uname -r 查看当前的内核版本

参考链接：https://www.toutiao.com/i7023555532728353294/

执行darknet下面的文件后出现新的问题

(yolov4) waq@waq-MS-7885:~/Downloads/ai/Vitis-AI-1.3.2/yolo_dploy/darknet-master$ ./darknet detector train  cfg/voc.data cfg/yolov4.cfg  yolov4.weights -map
CUDA status Error: file: ./src/dark_cuda.c : () : line: 38 : build time: Nov 22 2021 - 20:42:38 

 CUDA Error: unknown error
Darknet error location: ./src/dark_cuda.c, check_error, line #69
CUDA Error: unknown error: Bad file descriptor
(yolov4) waq@waq-MS-7885:~/Downloads/ai/Vitis-AI-1.3.2/yolo_dploy/darknet-master$ 

搜集资料发现是cuda的问题，哎，再重新装一次cuda！！！
1.官网下载安装文件，我这里下载的是run文件，安装之前卸载掉之前安装的旧版本cuda10.1（具体版本查看nvcc --version）
一般默认安装路径是/usr/local/ 下面，卸载旧版本 进入到 /usr/local/cuda-10.1/bin下面，执行 sudo ./cuda-uninstaller文件，最后成功卸载，可以紧接着删除文件夹即可
2.安装新下载的run文件

注意选择安装的时候不要勾选驱动，去掉x即可，其他的勾选，安装完之后会有一个summary：

  ===========
= Summary =
===========

Driver:   Not Selected
Toolkit:  Installed in /usr/local/cuda-10.1/
Samples:  Installed in /home/waq/, but missing recommended libraries

Please make sure that
 -   PATH includes /usr/local/cuda-10.1/bin
 -   LD_LIBRARY_PATH includes /usr/local/cuda-10.1/lib64, or, add /usr/local/cuda-10.1/lib64 to /etc/ld.so.conf and run ldconfig as root

To uninstall the CUDA Toolkit, run cuda-uninstaller in /usr/local/cuda-10.1/bin

Please see CUDA_Installation_Guide_Linux.pdf in /usr/local/cuda-10.1/doc/pdf for detailed information on setting up CUDA.
***WARNING: Incomplete installation! This installation did not install the CUDA Driver. A driver of version at least 418.00 is required for CUDA 10.1 functionality to work.
To install the driver using this installer, run the following command, replacing  with the name of this run file:
    sudo .run --silent --driver

Logfile is /var/log/cuda-installer.log

3.安装完成之后添加环境变量，在home目录下，ctrl+H打开隐藏的文件，找到.bashrc，打开添加路径（vi ~/vim .bashrc）
4.完成之后测试官方的例子，一直失败

  
  ./deviceQuery Starting...

 CUDA Device Query (Runtime API) version (CUDART static linking)

cudaGetDeviceCount returned 999
-> unknown error
Result = FAIL

5.只好重新装一遍驱动了。。。。。。。。。。
https://www.jianshu.com/p/8594771c7d5e
Loading new nvidia-495.44 DKMS files...
Building for 4.15.0-162-generic 4.15.0-163-generic
Building for architecture x86_64
Building initial module for 4.15.0-162-generic
Error! Bad return status for module build on kernel: 4.15.0-162-generic (x86_64)
Consult /var/lib/dkms/nvidia/495.44/build/make.log for more information.
Setting up nvidia-compute-utils-495 (495.44-0ubuntu0.18.04.1) ...
Warning: The home dir /nonexistent you specified can't be accessed: No such file or directory
Adding system user nvidia-persistenced' (UID 121) ... Adding new group nvidia-persistenced' (GID 127) ...
Adding new user nvidia-persistenced' (UID 121) with group nvidia-persistenced' ...
pam_tally2: /var/log/tallylog is either world writable or not a normal file
pam_tally2: Authentication error
useradd: failed to reset the tallylog entry of user "nvidia-persistenced"
Not creating home directory `/nonexistent'.
(哎，可能是上次跑一个程序的时候由于修改了gcc版本，导致安装失败)，接下里重新修改gcc版本。。。。
参考：
https://blog.csdn.net/JerryZhang__/article/details/108865176
https://forum.xanmod.org/thread-3635.html

sudo apt-get update
sudo apt-get install gcc-8
sudo apt-get install g++-8
cd /usr/bin
sudo rm gcc g++
sudo ln -s gcc-8 gcc
sudo ln -s g++-8 g++
https://blog.csdn.net/weixin_44128857/article/details/108554751

3.修改完gcc版本之后，安装cuda，然后再添加环境变量，最后测试

注意cuda版本需要对应，我截图中版本不同，所以需要将环境变量里面的版本修改为具体安装的版本

4.安装cudnn
安装cudnn
进入https://developer.nvidia.com/cudnn 下载对应的文件夹，解压,
注意：一定要和cuda的版本对应！！！

下载完成后解压并进入文件夹：

sudo cp cuda/include/cudnn.h /usr/local/cuda/include/ 
sudo cp cuda/lib64/libcudnn* /usr/local/cuda/lib64/ 
sudo chmod a+r /usr/local/cuda/include/cudnn.h 
sudo chmod a+r /usr/local/cuda/lib64/libcudnn*

在终端查看CUDNN版本：

cat /usr/local/cuda/include/cudnn.h | grep CUDNN_MAJOR -A 2
输出结果：

  #define CUDNN_MAJOR 7
#define CUDNN_MINOR 5
#define CUDNN_PATCHLEVEL 0
--
#define CUDNN_VERSION (CUDNN_MAJOR * 1000 + CUDNN_MINOR * 100 + CUDNN_PATCHLEVEL)

#include "driver_types.h"