sio0: port may not be enabled

[Alex Zbyslaw]

Marcel Moolenaar wrote:

>
> 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.
>
>
> 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.

Just a note that I get exactly the same issues with my BIOS/ACPI but *my 
serial port works*.  I have not needed to disable ACPI nor to use 
uart(4).  The sio0 line has an IRQ associated with it (4) and I think if 
there were really a problem there would be no IRQ here.

IIRC, the issue is something to do with ACPI presenting the serial ports 
backwards wrt the BIOS.  I know I got concerned about this when I first 
encountered it, and tried stuff to swap the two ports I have over, but 
nothing I did made the initial "ACPI probed irqs" error go away so I 
just tried the serial port and it worked.

--Alex