Re: [PATCH v2] x86: Early-boot serial I/O support

[Pekka Enberg]

On Sun, Jul 11, 2010 at 12:27 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 07/10/2010 02:17 PM, Pekka Enberg wrote:
>> On Sat, Jul 10, 2010 at 11:49 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>>> can you analyze "console=uart8250,io,0x3f8,115200n8" instead?
>>>
>>> that is equal to "earlyprintk=ttyS0,115200 console=ttyS0,115200"
>>>
>>> so we only use one for all.
>>>
>>> also like to kill earlyprintk=ttyS0,115200 to favor earlycon
>>
>> hpa, what's your take on this?
>>
>> The 'console' variant seems overly complicated to me. We can add it
>> but we also need to check for 'earlyprintk' as long as it's supported
>> by the kernel.
>>
>
> earlyprintk= seems to be preferred over console= these days.  Quite
> frankly it's idiotic to have the user enter as many low-level details as
> one has to do for the console= one.
>
> Now, as for the I/O base, the I/O base for legacy serial ports are
> available from a 4-element u16 array starting at absolute address 0x400.
>  I don't think Linux currently examines that array -- instead relying on
> the hard-coded values 0x3f8, 0x2f8, 0x3e8, 0x2e8 -- but it might
> something to consider for the future.  However, we should match the
> serial port subsystem there, of course.

OK. The current patch should match 'earlyprintk' handling which uses
hard-coded values only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/