I just pressed the reset button,and then the monitor failed to display anything. So I reflash the system with my host ubuntu computer, it showed sucessed, but the problem still exsited.I just can’t do anything,please help.
It is very common for the system to work, but video to not display because of various reasons. Consider that it is quite possible the Jetson is working fine, but you just don’t have video to show it.
Do you have access to the router or host where DHCP is served? Monitor logs or whatever is needed to see if a DHCP request was made…if so, the Jetson is probably working.
Can you ping the Jetson? If so, it is definitely working.
Can you ssh in to Jetson? If so, you can probably debug and work on things without too much effort. If not, you may need a serial console via the DB-9 connector (your host could use a serial-to-USB “serial UART” cable if no DB-9 is directly connected on the host). Some serial UART cables can have quirks, here’s one I know of which behaves well:
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When using the serial console via the DB-9 connector you would set your console program to speed 115200, 8-bits, no parity, one stop bit: 115200,8N1. If possible use CTS/DTS flow control (software flow control should always work if there is low noise and good signal, but CTS/DTS would be better since the DB-9 has those wires).
If video does not work, but the system is running, then you should suspect the automatic configuration method using the DDC/EDID line of the HDMI cable is not providing information which matches available modes. Older 15-pin D-sub VGA connectors do not have this, so using a VGA adapter would cause this. What kind of video cabling do you have, including any adapters?
Sometimes a hint that video runs but just isn’t seen is that when starting up the Jetson you may get a brief status light change on your monitor, and a note that scan rate is too fast…then nothing more as if it were not running. This would imply the monitor is seeing a signal but rejecting it for being out of its available range.