serial console on 8.x (probably sio vs uart)

Marcel Moolenaar xcllnt at
Fri Sep 12 03:40:06 UTC 2008

On Sep 11, 2008, at 7:09 PM, Garance A Drosihn wrote:

> After I boot up, the only /dev/tty* devices I have are ttyv0
> through ttyvf.  I've installed the new /etc/ttys and a new
> /boot/device.hints, though frankly device.hints has always
> been a magic-box to me, so I just blindly copied what was in
> GENERIC.hints and changed hint.uart.0.flags to be "0x30".

uart(4) does tell you when it's the console:

uart0: <16550 or compatible> port 0x3f8-0x3ff irq 4 on acpi0
uart0: [FILTER]
uart0: console (115200,n,8,1)

The first question is: do you see a line like the one above?
If not (most likely), try to boot explicitly with a serial
console (i.e. set boot_serial=yes at the loader prompt or
boot with -h).

>   I get the impression
> that the newer loader includes changes to make uart work better
> wrt the speed it expects to use on the serial port.  Is that a
> reasonable guess?

Nothing has been done to make uart(4) work. By default uart(4)
keeps the baudrate that the firmware or loader uses. This may
not always work, which is why you can tell uart(4) explicitly
what baudrate to use.

Marcel Moolenaar
xcllnt at

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