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From: Terry Lambert <terry@lambert.org>
Message-Id: <199611190010.RAA07981@phaeton.artisoft.com>
Subject: Re: UserConfig is broken + PS/2 support success
To: bde@zeta.org.au (Bruce Evans)
Date: Mon, 18 Nov 1996 17:10:14 -0700 (MST)
Cc: bde@zeta.org.au, yokota@zodiac.mech.utsunomiya-u.ac.jp,
        current@FreeBSD.org, nate@mt.sri.com, sos@FreeBSD.org
In-Reply-To: <199611171718.EAA22673@godzilla.zeta.org.au> from "Bruce Evans" at Nov 18, 96 04:18:12 am
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> >ISA/EISA
> >bit 5	0 Check parity form keyboard, with scan conversion (0 is 
> >	  normal operation).
> >	1 Ignore parity from keyboard, no scan conversion.

[ ... ]

> I think I know what bit 5 does: setting it makes XT keyboards work.  XT
> keyboards send scancodes that don't need any conversion (see Van Gilluwe).
> However, I couldn't get this to work in practice for an old keyboard with 
> an XT/AT switch.  Neither the BIOS nor standard syscons nor syscons
> tweaked to set the bit can see the keyboard in XT mode, and the tweaked
> syscons can see the keyboard in AT mode.  Perhaps my keyboard controller
> is MCA compatible.

It should be noted that Windows 95's VKD code (again, from the DDK) does
a keyboard disable during the mouse probe phase, and goes so far as to
call VPICD_Physically_Mask and VPICD_Clear_Int_Request to insure no one
can do anything to the keyboard in the interim.

Since if the probe is false, these bits are restored by the PS/2 mouse
(Virtual Auxillary Device, or VAD) driver, I don't think this will
damage the PS/2 mouse case.

Maybe if the mouse is not probed true, these bits could be restored
to their previous values?  This would fix your complaint about XT keyboards
on non-MCA keyboard controller chips.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.