From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751259AbaCLEAz (ORCPT ); Wed, 12 Mar 2014 00:00:55 -0400 Received: from smtp.nue.novell.com ([195.135.221.5]:36332 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751070AbaCLEAy (ORCPT ); Wed, 12 Mar 2014 00:00:54 -0400 Subject: Re: [RESEND] Fast TSC calibration fails with v3.14-rc1 and later From: joeyli To: Julian Wollrath Cc: Thomas Gleixner , x86@kernel.org, LKML , Lee@linutronix.de, "Rafael J. Wysocki" In-Reply-To: <20140311181513.0f73383c@ilfaris> References: <20140310110410.5b2218f6@ilfaris> <20140311142910.27594027@ilfaris> <20140311181513.0f73383c@ilfaris> Content-Type: text/plain; charset="UTF-8" Date: Wed, 12 Mar 2014 12:00:07 +0800 Message-ID: <1394596807.26565.135.camel@linux-s257.site> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Julian, 於 二，2014-03-11 於 18:15 +0100，Julian Wollrath 提到： > Am Tue, 11 Mar 2014 14:56:41 +0100 (CET) > schrieb Thomas Gleixner : > > > Ok, via bisecting I found commit > > > 73f7d1ca32638028e3271f54616773727e2f9f26 (see below) to be the one > > > that introduced this regression. > > > > Interesting. I have no idea what's going on. But maybe can the ACPI > > folks shed some light on it. > My patch moved acpi_early_init() to before timekeeping_init() is for prepare the later using ACPI TAD to set system clock. I think that because acpi_early_init() setup SCI interrupt and enable acpi subsystem, it causes fast TSC calibration fail. > I have absolutely no idea, if it is the right thing to do and why it > works, but the patch below fixes the problem. Thank you for your help. > > > Cheers, > Julian Wollrath > > From 7664f495039d93adfce073e58840a46549904f04 Mon Sep 17 00:00:00 2001 > From: Julian Wollrath > Date: Tue, 11 Mar 2014 18:05:43 +0100 > Subject: [PATCH] Fix fast TSC calibration > > Since commit 73f7d1ca32638028e3271f54616773727e2f9f26 the fast TSC calibration > failed on a Thinkpad X121e with an AMD E450 APU. Moving acpi_early_init() after > late_time_init() fixes this. > > Signed-off-by: Julian Wollrath > --- > init/main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/init/main.c b/init/main.c > index eb03090cdced..bf9d99148bd6 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -561,7 +561,6 @@ asmlinkage void __init start_kernel(void) > init_timers(); > hrtimers_init(); > softirq_init(); > - acpi_early_init(); > timekeeping_init(); > time_init(); > sched_clock_postinit(); > @@ -609,6 +608,7 @@ asmlinkage void __init start_kernel(void) > numa_policy_init(); > if (late_time_init) > late_time_init(); > + acpi_early_init(); > sched_clock_init(); > calibrate_delay(); > pidmap_init(); The late_time_init() dependent on timekeeping_init(), if we don't want move acpi_early_init() before timekeeping_init() then just direct put it before efi_enter_virtual_mode() because we tested this changed. This patch restricts the position to run acpi_early_init() before timekeeping_init() when only "CMOS RTC Not Present" bit set in FADT. Could you please help to test it on your machine? Thanks a lot! Joey Lee >>From 8ef4fff76dd2f50bef1e8eb9c96f3b0228a38401 Mon Sep 17 00:00:00 2001 From: Lee, Chun-Yi Date: Wed, 12 Mar 2014 11:36:32 +0800 Subject: [PATCH] ACPI / init: Run acpi_early_init() before timekeeping_init() when CMOS RTC Not Present bit set This is a variant patch from Rafael J. Wysocki's ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode() According to Matt Fleming, if acpi_early_init() was executed before efi_enter_virtual_mode(), the EFI initialization could benefit from it, so Rafael's patch makes that happen. And, later we want accessing ACPI TAD device to set system clock, so move acpi_early_init() before timekeeping_init() when "CMOS RTC Not Present" bit set. This position is also before efi_enter_virtual_mode(). Signed-off-by: Lee, Chun-Yi --- init/main.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/init/main.c b/init/main.c index eb03090..e1b69d2 100644 --- a/init/main.c +++ b/init/main.c @@ -561,7 +561,9 @@ asmlinkage void __init start_kernel(void) init_timers(); hrtimers_init(); softirq_init(); - acpi_early_init(); + if (acpi_gbl_FADT.header.revision >= 5 && + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) + acpi_early_init(); timekeeping_init(); time_init(); sched_clock_postinit(); @@ -613,6 +615,9 @@ asmlinkage void __init start_kernel(void) calibrate_delay(); pidmap_init(); anon_vma_init(); + if (!(acpi_gbl_FADT.header.revision >= 5 && + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC)) + acpi_early_init(); #ifdef CONFIG_X86 if (efi_enabled(EFI_RUNTIME_SERVICES)) efi_enter_virtual_mode(); -- 1.6.4.2