[NVIDIA development board] FAQ (updated from time to time)

It's estimated that I'll be with you for a long time Nvidia Dealing with the development board of , Record some problems encountered

1. ssh Try to connect nvidia The board , Report the following error

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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:9XvufSSIeZ7MAurIZ1Qw9Z13YV1Zcim2kthmAlECgYw.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /root/.ssh/known_hosts:8
ECDSA host key for 192.168.122.100 has changed and you have requested strict checking.
Host key verification failed.
lost connection

There is a simple and crude way , hold ssh Under the known_hosts Just delete the folder
rm -rf ~/.ssh/known_hosts
If you worry about other problems , First copy A backup , If something happens, you can recover cp ~/.ssh/known_hosts ~/.ssh/known_hosts_bak

After deleting , It should be ssh In the past the , Pro feasible measurement

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2. Nvidia The fan on the board doesn't work , The temperature is high 60° Above

First check the current fan speed ,
cat /sys/devices/pwm-fan/target_pwm
If it shows 0, It means that the current fan does not turn , The value is the current speed

There are two ways to set the speed

• The first is to give a specified speed directly , Keep the fan running , But restart will fail
• The second setting is startup

1） The first method
Enter the following command to set the current fan speed ：
sudo sh -c "echo 200 > /sys/devices/pwm-fan/target_pwm"
remember , This is just a one-off , No more after restart .

2） The second method

① Write a script to start the fan , stay /usr/bin/ Create mirror-fan Folder , establish mirror-fan.sh file

set -x
set -e

filepath="/sys/devices/pwm-fan/target_pwm"
echo 0 > ${filepath}

sleep 5

echo 200 > ${filepath}
exit 0

② Create boot entry , stay /lib/systemd/system/ Create under directory mirror-fan.service

[Unit]
Description=Mirror fan

[Service]
User=root
Type=simple
ExecStart=/bin/bash /usr/bin/mirror-fan/mirror-fan.sh

[Install]
WantedBy=multi-user.target

③ Open one terminal, Then input sudo systemctl enable mirror-fan.service
④ Restart to see if it takes effect

3. Remote shutdown / Restart command
   To turn it off ：sudo poweroff
   restart ：sudo reboot