Subject: Re: wsdisplay, early consoles etc.
To: Bill Studenmund <wrstuden@netbsd.org>
From: Michael Lorenz <macallan@netbsd.org>
List: tech-kern
Date: 11/05/2006 13:36:07
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Hello,

On Nov 5, 2006, at 12:32, Bill Studenmund wrote:

> On Sat, Nov 04, 2006 at 01:54:02PM -0500, Michael Lorenz wrote:
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>> Hello,
>>
>> On Oct 26, 2006, at 13:36, Michael Lorenz wrote:
>>
>>> Besides that - we should come up with a generic interface to let a
>>> driver find out if it's supposed to become the system console or not.
>>> On OpenFirmware machines that's easy - just check /choosen/stdout -
>>> but it's ugly to have OF-dependencies in drivers that reside in
>>> sys/dev/pci. Maybe we should just have the MD autoconf code attach
>>> properties for:
>>> - - console
>>> - - display mode
>>> - - font
>>> - - whatever I can't think of right now
>>
>> I guess no protest means no objections?
>
> For some reason, I'm having a negative reaction to the use of 
> "overwrite".
> And I'm not sure if it's really a problem or not.

During autoconf it's not as far as I can tell.

> I think I like the idea of being able to use a simple console driver 
> then
> update to a more sophisiticated one once we know the hardware. And I 
> like
> the idea about MI console description.

My main motivation is the problem we'd have with selecting an early 
console driver before autoconf runs. We'd need some sort of 
mini-autoconf before autoconf so better have some simple catch-all and 
let autoconf select the one we'll end up using.

> So let me try this question. Why should the console be updated only 
> once?

Good question - mainly because the current wsdisplay_cnattach() has a 
KASSERT() that makes sure it's only called exactly once and I'd assume 
whoever put it there had a good reason to do so.
I'm not sure what would break if we'd allow moving the console around 
at runtime - probably not much.

have fun
Michael
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