From owner-freebsd-current@FreeBSD.ORG Wed Sep 29 13:26:04 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E10B91065693; Wed, 29 Sep 2010 13:26:03 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id AE3188FC43; Wed, 29 Sep 2010 13:26:03 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 598C046C08; Wed, 29 Sep 2010 09:26:03 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id A42B98A050; Wed, 29 Sep 2010 09:26:02 -0400 (EDT) From: John Baldwin To: freebsd-current@freebsd.org Date: Wed, 29 Sep 2010 09:14:08 -0400 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20100819; KDE/4.4.5; amd64; ; ) References: <201009291207.53146.naylor.b.david@gmail.com> <4CA317BA.8070903@FreeBSD.org> <4CA324EB.4040500@icyb.net.ua> In-Reply-To: <4CA324EB.4040500@icyb.net.ua> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201009290914.08513.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Wed, 29 Sep 2010 09:26:02 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Alexander Motin , David Naylor , Andriy Gapon Subject: Re: Safe-mode on amd64 broken X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Sep 2010 13:26:04 -0000 On Wednesday, September 29, 2010 7:37:15 am Andriy Gapon wrote: > on 29/09/2010 13:40 Alexander Motin said the following: > > Hi. > > > > David Naylor wrote: > >> Trying to boot a recent (sep 23) amd64 kernel in safe-mode fails with ``panic: > >> No usable event timer found!''. This occurs on two (all my) machines. This > >> has been a persistent problem since the introduction of the event timer code. > > > > I've reproduced the problem. > > > > The reason is that all (or at least most) of devices (both PCI and ISA), > > including only available in that mode i8254 and RTC timers, failed to > > allocate their interrupts. While reported message is indeed related to > > event timer code, problem IMHO doesn't. While without this panic system > > could boot without any alive timer, I have doubts that it would be > > functional without timers, USB, network and disk controllers. > > > > Problems seems to be the same if I am trying to boot without ACPI. Probably the kernel doesn't have 'device atpic' so disabling APIC probably breaks all interrupts. A newer system might only describe APICs via the ACPI MADT table and not provide an MP Table. In that case disabling ACPI would effectively disable APIC leading to the same result. > It's interesting to see what the "Safe Mode" really is: > dup bootsafekey @ = if > s" arch-i386" environment? if > drop > s" acpi_load" unsetenv > s" 1" s" hint.acpi.0.disabled" setenv > s" 1" s" loader.acpi_disabled_by_user" setenv > s" 1" s" hint.apic.0.disabled" setenv > then > s" 0" s" hw.ata.ata_dma" setenv > s" 0" s" hw.ata.atapi_dma" setenv > s" 0" s" hw.ata.wc" setenv > s" 0" s" hw.eisa_slots" setenv > s" 1" s" hint.kbdmux.0.disabled" setenv > 0 boot > > > Not sure if disabling ACPI on modern hardware is a good idea. > Even more unsure about disabling APIC. > > Makes me wonder what this could be useful for. > Perhaps, these are just leftovers from times were ACPI, APIC (and ATA DMA) were > all new and unproven things. Yes, on modern machines I think disabling ACPI and APIC is less safe actually. -- John Baldwin