From owner-cvs-sys  Thu Jul 10 00:33:16 1997
Return-Path: <owner-cvs-sys>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.5/8.8.5) id AAA12485
          for cvs-sys-outgoing; Thu, 10 Jul 1997 00:33:16 -0700 (PDT)
Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19])
          by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id AAA12476;
          Thu, 10 Jul 1997 00:33:08 -0700 (PDT)
Received: (from bde@localhost) by godzilla.zeta.org.au (8.8.5/8.6.9) id RAA27929; Thu, 10 Jul 1997 17:27:14 +1000
Date: Thu, 10 Jul 1997 17:27:14 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199707100727.RAA27929@godzilla.zeta.org.au>
To: brian@freebsd.org, cvs-all@freebsd.org, cvs-committers@freebsd.org,
        cvs-sys@freebsd.org
Subject: Re: cvs commit: src/sys/i386/isa syscons.c
Sender: owner-cvs-sys@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

>brian       1997/07/09 07:10:21 PDT
>
>  Modified files:
>    sys/i386/isa         syscons.c 
>  Log:
>  Don't allow CONS_HISTORY ioctl to alter history pointers
>  while in "scroll mode" (return EBUSY).
>  Suggested by:	Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp>

There are probably a lot of ioctls that do similar bad things.  E.g., in
scroll mode, the VGA mode ioctls at best clear the wrong part of the
off-screen buffer.

Scroll mode should probably be handled as if there is no foreground
process.  Background processes are supposed to sleep in ioctl() if the
ioctl would modify the state (see the isbackground() tests in kern/tty.c).
This doesn't actually work right, because tty.c doesn't know about many
device-specific ioctls and many tty device drivers don't know about tty.c.

Bruce