com1 incorrectly associated with ttyd1, com2 with ttyd0

John Baldwin jhb at freebsd.org
Fri Dec 16 08:25:06 PST 2005


On Friday 16 December 2005 01:36 am, Joe Rhett wrote:
> > > On Thu, Dec 01, 2005 at 08:58:04PM +1100, Bruce Evans wrote:
> > > > It's not clear that disabling in the BIOS should disable for all
> > > > OSes.
> >
> > On Monday 05 December 2005 03:05 pm, Joe Rhett wrote:
> > > What?  That's a fairly weird interpretation.  If I want to disable
> > > inside a given OS, I do that inside the OS.  If I want to disable for
> > > _ALL_ OSes, then I disable in the BIOS.  What reasonable logic can
> > > argue otherwise?
>
> On Mon, Dec 05, 2005 at 03:22:40PM -0500, John Baldwin wrote:
> > The BIOS doesn't say "X is disabled", it just doesn't have any resources
> > setup for X.
>
> Well, this is where what the BIOS "says" and what the user is led to
> expect, are different that what you are arguing for.  And on top of that,
> every major OS except for FreeBSD does the right thing (acts like it isn't
> there)
>
> Isn't it fairly obvious that no resources setup for a peripheral means
> "disabled in BIOS" and it would be best to ignore that resource?

No.  You would understand that if you had actually read my earlier e-mails.  
If you set PnP OS to yes, then the BIOS is free to not enable any devices not 
needed for booting.  Thus, even if you didn't have COM1 disabled if it didn't 
need COM1 to boot and you had PnP OS set to yes, it could not assign any 
resources to COM1 and require the OS to set the resources.  There isn't any 
way for the OS to know if you disabled the device, or if you used PnP OS and 
the BIOS didn't configure that device _even_ _though_ _it_ _is_ _enabled_ 
_in_ _the_ _BIOS_ _setup_ because it didn't feel like it.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org


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