From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [ACPI] Re: [BKPATCH] LAPIC fix for 2.6 Date: Mon, 11 Oct 2004 13:42:11 +0200 Sender: linux-kernel-owner@vger.kernel.org Message-ID: <20041011114211.GF14615@wotan.suse.de> References: <1097429707.30734.21.camel@d845pe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: To: Linus Torvalds Cc: "Maciej W. Rozycki" , Len Brown , Andrew Morton , Kernel Mailing List , ACPI Developers List-Id: linux-acpi@vger.kernel.org On Sun, Oct 10, 2004 at 05:47:05PM -0700, Linus Torvalds wrote: > > > On Sun, 10 Oct 2004, Maciej W. Rozycki wrote: > > > > Hmm, any particular reason to keep the local APIC disabled by default? > > Yes. It changes interrupt handling, so any SMM stuff tends to break on > BIOSes that don't know about APICs. Things like the magic keys etc. It > apparently also breaks some ACPI stuff (likely AML code that "knows" that > interrupts are done with the legacy controller). > > Mostly a laptop issue, I suspect - simply because desktops don't do > anything strange these days. It's more than a laptop issue. Especially older desktops still don't work with APIC by default, and even a lot of modern ones have problems. It works around ACPI bugs. Some common issues I ran into on x86-64: nvidia nforce2/3 is still often broken because of the bogus timer override so many BIOS have) Some VIA K8 boards get mysterious IDE DMA errors after some time when the APIC is on. [Patch for the Nvidia thing is pending - just always ignore it - but not submitted yet for i386 yet. x86-64 has it fixed in -mm*] -Andi