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From: hm@altona.hamburg.com (Hellmuth Michaelis)
Subject: Re: "Bug" in syscons?
To: sos@FreeBSD.org
Date: Thu, 16 Nov 1995 07:45:28 +0100 (MET)
Cc: bde@zeta.org.au, darrylo@hpnmhjw.sr.hp.com, freebsd-bugs@FreeBSD.org,
        freebsd-questions@FreeBSD.org
In-Reply-To: <199511152214.XAA00502@SandBox> from "Soren Schmidt" at Nov 15, 95 11:14:04 pm
Reply-To: hm@altona.hamburg.com
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> > In set_font_mode():
> > old:
> > >      outb(TSIDX, 0x02); outb(TSREG, 0x04);
> > >!     outb(TSIDX, 0x04); outb(TSREG, 0x06);
> > >      outb(GDCIDX, 0x04); outb(GDCREG, 0x02);
> > >      outb(GDCIDX, 0x05); outb(GDCREG, 0x00);
> > >!     outb(GDCIDX, 0x06); outb(GDCREG, 0x05);
> > new:
> > >      outb(TSIDX, 0x02); outb(TSREG, 0x04);
> > >!     outb(TSIDX, 0x04); outb(TSREG, 0x07);
> > >      outb(GDCIDX, 0x04); outb(GDCREG, 0x02);
> > >      outb(GDCIDX, 0x05); outb(GDCREG, 0x00);
> > >!     outb(GDCIDX, 0x06); outb(GDCREG, 0x00);
> > 
> > TS reg 4 bit 0x01 is "Reserved" for the ET4000.  Better not use it.

This is correct and i wonder where i got it from (for pcvt).

But, my very first chipset to support this was and still is a ET4000 and
it runs just fine.

>From the Ferraro book: bit 0 selects between alpha and graphics mode on
an EGA (!!) 0=graphics 1=alphanumerics.

> > GDC reg 6 bit 0x01 is "Graphics mode enable"; bits 0x04 and 0x08
> > select the memory map:
> > 	0x00: 128K at 0xA0000
> > 	0x04:  64K at 0xA0000
> > 	0x08:  32K at 0xB0000
> > 	0x0C:  32K at 0xB8000

This might be the cause of the problem, bit 0 selects for a VGA what the
above described bit selects for a VGA: 0=alphanumerics, 1=graphics.

hellmuth
-- 
Hellmuth Michaelis           hm@altona.hamburg.com              Hamburg, Europe
                                              (A)bort, (R)etry, (I)nstall BSD ?