sio0: port may not be enabled

[Marcel Moolenaar]

On Apr 20, 2007, at 8:23 AM, Jeremy Chadwick wrote:

> Look closely at the dmesg line, note what device sio0 is claiming  
> to be
> associated with (acpi0, not isa0):
>
>> sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags  
>> 0x10 on acpi0
>
> This is one of the drawbacks to using ACPI.

This is not a drawback. It's partly why ACPI was designed and  
implemented:
to describe legacy hardware.

> Some systems apparently tie the serial port to ACPI functionality in a
> different way.  For example, I have a couple boxes which have sio0
> attached to acpi0 that work fine.  In some other cases, I have ones
> which result in a non-working serial port unless I disable ACPI (thus
> sio0 shows up as being attached to isa0).

Could you try uart(4) instead. It seems quite excessive to have to
disable ACPI just to get a serial port working. I'd like to know
if this is related to the sio(4) driver or something else.

Thanks,

-- 
Marcel Moolenaar
xcllnt at mac.com