Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755928AbYGOWYR (ORCPT ); Tue, 15 Jul 2008 18:24:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753498AbYGOWYD (ORCPT ); Tue, 15 Jul 2008 18:24:03 -0400 Received: from atlantis.8hz.com ([212.129.237.78]:55314 "EHLO atlantis.8hz.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751661AbYGOWYB (ORCPT ); Tue, 15 Jul 2008 18:24:01 -0400 Date: Tue, 15 Jul 2008 22:23:59 +0000 From: Sean Young To: "H. Peter Anvin" , Jeremy Fitzhardinge , Rusty Russell , linux-kernel@vger.kernel.org Subject: Re: Regression: boot failure on AMD Elan TS-5500 Message-ID: <20080715222359.GA70973@atlantis.8hz.com> References: <200806162327.34912.rusty@rustcorp.com.au> <48566C88.6000702@goop.org> <20080616161944.GA53539@atlantis.8hz.com> <20080630214347.GA57988@atlantis.8hz.com> <4869558A.9020907@goop.org> <48695871.8000805@zytor.com> <48695F88.9080905@goop.org> <48696167.6050000@zytor.com> <20080701195942.GA76608@atlantis.8hz.com> <20080701202014.GA77013@atlantis.8hz.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080701202014.GA77013@atlantis.8hz.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2211 Lines: 63 On Tue, Jul 01, 2008 at 08:20:14PM +0000, Sean Young wrote: > On Tue, Jul 01, 2008 at 07:59:42PM +0000, Sean Young wrote: > > On Mon, Jun 30, 2008 at 03:42:47PM -0700, H. Peter Anvin wrote: > > > diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S > > > index ab049d4..141b6e2 100644 > > > --- a/arch/x86/boot/pmjump.S > > > +++ b/arch/x86/boot/pmjump.S > > > @@ -33,6 +33,8 @@ protected_mode_jump: > > > movw %cs, %bx > > > shll $4, %ebx > > > addl %ebx, 2f > > > + jmp 1f # Short jump to serialize on 386/486 > > > +1: > > > > > > movw $__BOOT_DS, %cx > > > movw $__BOOT_TSS, %di > > > @@ -40,8 +42,6 @@ protected_mode_jump: > > > movl %cr0, %edx > > > orb $X86_CR0_PE, %dl # Protected mode > > > movl %edx, %cr0 > > > - jmp 1f # Short jump to serialize on 386/486 > > > -1: > > > > > > # Transition to 32-bit mode > > > .byte 0x66, 0xea # ljmpl opcode > > > > I'm afraid it doesn't work. Maybe I can find something in the AMD Elan > > documentation. Would a fence make sense? > > I was just trying to confirm this with postive and negative tests which > is failing. I'm probably being an idiot, please let systematically test > this. When I bisected this issue between latest and 2.6.23 the issue seemed to be here (round about 2.6.24-rc1). Trying to repeat the same things on latest just led to confusion. So I've started from scratch with contemporary trees and found something very different. 2.6.25: works 2.6.25.5: works 2.6.25.6: broken 2.6.25.10: broken 2.6.26: works Now the issue which was introduced in 2.6.25.6 is that a rdtsc will be done even though this CPU does not support it (before console_init(), leaving me with only one led for output!). This issue has been fixed in 2.6.26 but not in 2.6.25-stable. The protected mode jump was just a red herring (or at least whatever was broken back then is fixed now); 2.6.26 is working fine and that's good enough for me. Thanks for all the help, Sean -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/