From owner-freebsd-current Tue Dec 29 07:57:44 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA12834 for freebsd-current-outgoing; Tue, 29 Dec 1998 07:57:44 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from outmail.utsunomiya-u.ac.jp (outmail.utsunomiya-u.ac.jp [160.12.196.3]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA12823 for ; Tue, 29 Dec 1998 07:57:35 -0800 (PST) (envelope-from yokota@zodiac.mech.utsunomiya-u.ac.jp) Received: from zodiac.mech.utsunomiya-u.ac.jp (IDENT:m6EwNtcSnfkU+MWp3xJOVJxizp1Mfyap@zodiac.mech.utsunomiya-u.ac.jp [160.12.42.1]) by outmail.utsunomiya-u.ac.jp (8.9.1/8.9.1) with ESMTP id AAA30583; Wed, 30 Dec 1998 00:56:09 +0900 (JST) Received: from zodiac.mech.utsunomiya-u.ac.jp (zodiac.mech.utsunomiya-u.ac.jp [160.12.42.1]) by zodiac.mech.utsunomiya-u.ac.jp (8.7.6+2.6Wbeta7/3.4W/zodiac-May96) with ESMTP id AAA16643; Wed, 30 Dec 1998 00:58:21 +0900 (JST) Message-Id: <199812291558.AAA16643@zodiac.mech.utsunomiya-u.ac.jp> To: Mike Smith cc: current@FreeBSD.ORG, yokota@zodiac.mech.utsunomiya-u.ac.jp Subject: Re: future of syscons In-reply-to: Your message of "Mon, 28 Dec 1998 15:10:39 PST." <199812282310.PAA13485@dingo.cdrom.com> References: <199812282310.PAA13485@dingo.cdrom.com> Date: Wed, 30 Dec 1998 00:58:06 +0900 From: Kazutaka YOKOTA Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >> It is true that IRQ 1 is always assigned to the keyboard controller on >> the AT motherboard and no device can claim it because IRQ 1 line is >> not available in expansion slots. >> >> The PS/2 mouse interrupt IRQ 12 is another story. IRQ 12 is available >> to ISA and PCI bus slots and you can assign it to a device! We >> shouldn't make the keyboard controller code to claim IRQ 12 when >> either 1) a PS/2 mouse is not detected, or 2) another device is using >> or going to use IRQ 12. > >Sure; by all means disable the interrupt handler if a ps/2 mouse is not >found, I think that "disabling the interrupt handler" is not enough, the IRQ 12 resource must be released and made available to other devices to claim. >but it's important to claim the interrupt in the keyboard >controller code if one *is* found, Yes. > or even just expected to be found (eg. attached after bootup). Well, as I wrote before, ISA cards can be set to use IRQ 12, or the PCI interrupt may be mapped to this IRQ. Therefore, when no PS/2 mouse is detected at boot time, it can safely claim the IRQ 12 only if the IRQ is not used by any other devices. # The PS/2 mouse port is generally not designed for "hot plugging". # Thus, in general it is very little use reserving the IRQ 12 if the mouse # is not detected at boot time; the mouse won't be connected later. Kazu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message