Linux stop aboout 4 second, after console [tty0] enabled, bootconsole disabled

Connect serial console to the J21(8,9,10)
Flash the official Jetpack3.3 Image to TX2, kernel start-up and stop at (console [tty0] enabled, bootconsole disabled) about 4 second.
Flash Our customer kernel, it stop here about 8 seconds.
This seriously increase the system startup time. How to resolved it?
What happen after kernel output the message “bootconsole disabled”?

hello 27653276,

please also check with loopback node.
suggest you also refer to Topic 1056152 for using UART0 with TX2.


Thank you for your quickly response.
Sorry, I still not know what’s the reason on kernel start-up stop after "bootconsole disabled ".
As for your suggestion:
please also check with loopback node.// For your comment, I don’t see dev node file loopback in /dev/.
How to check that? can you explain it more detail?
suggest you also refer to Topic 1056152 for using UART0 with TX2.// Currently the serial console use UART1.
it will cause the issues?


You might want to post the serial console output log up until it stops.

FYI, if “/dev/ttyS0” is serial console, and if activity is seen on that port during U-Boot stage, then you will drop into the U-Boot console. Are you using ttyS0 as a serial console, or as a general UART?

On a non-serial console UART loopback would mean directly wiring its own TX and RX together (and optionally also wiring its own CTS and RTS together if flow control is used). Then using a single serial console program to see if echo occurs as you type. Having echo means the current settings are valid and should work when talking to another UART if that other UART is using the same settings. UARTs don’t generally speak up when one talks to another with the wrong settings, but loopback implies the UART will always agree with itself (oddly, talking to itself is a kind of sanity check).

If you are using only UART1 and have access to its “/dev/ttyTHS#”, then something like gtkterm or minicom could be used on that port and echo would indicate correct function.