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Date:      Tue, 10 Sep 1996 23:28:26 -0700
From:      Arve Ronning <arver@sn.no>
To:        Bruce Evans <bde@zeta.org.au>
Cc:        Arve.Ronning@alcatel.no, freebsd-hackers@freebsd.org
Subject:   Re: Support for fixed-scan monitors
Message-ID:  <32365C0A.B12@sn.no>
References:  <199609091752.DAA23576@godzilla.zeta.org.au>

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Bruce Evans wrote:
> 
> [Arve wrote:]
> 
> >However, what if the screen used by BIOS is on a monitor which doesn't accept the
> >default scan rates (my situation) ? During boot, we would not see :
> >a) the BIOS messages
> >b) the '>> FreeBSD....Boot:' prompt
> >In this case, there is little we can do about a) (except perhaps hack the BIOS :(.
> >But we *can* do something about b) by hacking the bootblocks (which is what I did:).
> 
> How do you stop the BIOS from blowing up the monitor that doesn't accept
> normal scan rates? :-).

Don't switch on the monitors main power until *after* X has been started.
(there's a MDA/Hercules monitor where I can see what I'm doing, remember:).

> 
> I deleted your mail with the bootblock changes.  How does it set to mono
> mode?  Does it just set mode 7?  I'm surprised that you can't set the
> value in the CMOS.
> 

It does: byte *(0:0x410) |= 0x30; Then uses int 0x10 to set mode 7, 
cursor position & shape.

I'm surprised too that this can't be done simply by entering setup and
telling BIOS to use the MDA/Herc. But (as I've said in an earlier mail),
the BIOSes I've tried failed either by silently reverting to VGA or by
failing to initialize both screen adapters properly on the next power-on
boot. Now, this may just be caused by my bad luck, but I tried it with
two different MDAs and a ISA VGA on two different BIOSes and with one
of the MDAs and a PCI VGA on a third BIOS. No go :(.
I'm not complaining about BIOSes. What I'm saying is simply : don't 
expect any BIOS to function properly in this area.

Regards		- Arve




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