Normal baudrate for Rockchip boards

[psychedup]

There's a couple of places to look. First, there's usually a kernel command line argument that tells it what speed to use for dmesg output when booting. For example, on my PineA64+ in /boot/uEnv.txt:

Code:

console=tty0 console=ttyS2,115200n8 no_console_suspend
kernel_filename=pine64/Image
initrd_filename=initrd.img
#fdt_filename_prefix=pine64/sun50i-a64-tp-
fdt_filename_prefix=pine64/sun50i-a64-hdmi-
optargs=disp.screen0_output_mode=1080p60

the "console=ttyS1,115200n8" is setting the serial port speed.

On my Rock64 I don't see that, but in /boot/efi/extlinux/extlinux.conf looks like this:

Code:

timeout 30
default kernel-4.4.138
menu title select kernel

label kernel-4.18.0-rc8
   kernel /Image-4.18.0-rc8
   initrd /initrd.img
   fdt /dtb-4.18.0-rc8
   append rw root=UUID=2791c0dd-f329-4734-adc7-aebb589fdb53 rootwait rootfstype=ext4 panic=10 init=/sbin/init coherent_pool=1M ethaddr=${ethaddr} eth1addr=${eth1addr} serial=${serial#} cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory swapaccount=1

I wonder if that "{serial#}" is something being passed to the kernel by u-boot?

Besides the command line, you also want to look at /etc/inittab. There should be a line similar to this:

Code:

s2:12345:respawn:/sbin/agetty -L 115200 ttyS2 vt100

Your serial port might be some other device besides ttyS2 - but the 115200 on this line is setting the serial port speed for logins over this serial port.

Hope that helps a little.

Chris