Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752824AbbFKJgk (ORCPT ); Thu, 11 Jun 2015 05:36:40 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:35691 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750930AbbFKJgb (ORCPT ); Thu, 11 Jun 2015 05:36:31 -0400 Message-ID: <55795693.2060805@linaro.org> Date: Thu, 11 Jun 2015 17:36:19 +0800 From: Hanjun Guo User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Toshi Kani , ACPI Devel Maling List , Linux Kernel Mailing List , Len Brown , Marius Tolzmann , Matt Fleming , Chun-Yi , Aaron Lu , Lv Zheng Subject: Re: [PATCH] ACPI / init: Switch over platform to the ACPI mode later References: <12578608.kKCTgirQ6f@vostro.rjw.lan> <13170654.9h99FfQLut@vostro.rjw.lan> <55779BB0.6030900@linaro.org> <2586130.FMgQktF91L@vostro.rjw.lan> In-Reply-To: <2586130.FMgQktF91L@vostro.rjw.lan> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4883 Lines: 105 On 06/11/2015 07:17 AM, Rafael J. Wysocki wrote: > On Wednesday, June 10, 2015 10:06:40 AM Hanjun Guo wrote: >> On 06/10/2015 07:48 AM, Rafael J. Wysocki wrote: >>> On Wednesday, June 03, 2015 11:13:57 AM Toshi Kani wrote: >>>> On Sat, 2015-05-30 at 14:21 +0200, Rafael J. Wysocki wrote: >>>>> From: Rafael J. Wysocki >>>>> >>>>> Commit 73f7d1ca3263 "ACPI / init: Run acpi_early_init() before >>>>> timekeeping_init()" moved the ACPI subsystem initialization, >>>>> including the ACPI mode enabling, to an earlier point in the >>>>> initialization sequence, to allow the timekeeping subsystem >>>>> use ACPI early. Unfortunately, that resulted in boot regressions >>>>> on some systems and the early ACPI initialization was moved toward >>>>> its original position in the kernel initialization code by commit >>>>> c4e1acbb35e4 "ACPI / init: Invoke early ACPI initialization later". >>>>> >>>>> However, that turns out to be insufficient, as boot is still broken >>>>> on the Tyan S8812 mainboard. >>>>> >>>>> To fix that issue, split the ACPI early initialization code into >>>>> two pieces so the majority of it still located in acpi_early_init() >>>>> and the part switching over the platform into the ACPI mode goes into >>>>> a new function, acpi_subsystem_init(), executed at the original early >>>>> ACPI initialization spot. >>>>> >>>>> That fixes the Tyan S8812 boot problem, but still allows ACPI >>>>> tables to be loaded earlier which is useful to the EFI code in >>>>> efi_enter_virtual_mode(). >>>>> >>>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=97141 >>>>> Reported-and-tested-by: Marius Tolzmann >>>>> Signed-off-by: Rafael J. Wysocki >>>> >>>> Can you add comments to acpi_early_init() and acpi_subsystem_init() to >>>> clarify what ACPI features are enabled at each phase, and what >>>> dependency they have in the boot sequence? (The same goes to >>>> early_acpi_boot_init() and acpi_boot_init().) >>> >>> OK, update follows. >>> >>> --- >>> From: Rafael J. Wysocki >>> Subject: ACPI / init: Switch over platform to the ACPI mode later >>> >>> Commit 73f7d1ca3263 "ACPI / init: Run acpi_early_init() before >>> timekeeping_init()" moved the ACPI subsystem initialization, >>> including the ACPI mode enabling, to an earlier point in the >>> initialization sequence, to allow the timekeeping subsystem >>> use ACPI early. Unfortunately, that resulted in boot regressions >>> on some systems and the early ACPI initialization was moved toward >>> its original position in the kernel initialization code by commit >>> c4e1acbb35e4 "ACPI / init: Invoke early ACPI initialization later". >>> >>> However, that turns out to be insufficient, as boot is still broken >>> on the Tyan S8812 mainboard. >>> >>> To fix that issue, split the ACPI early initialization code into >>> two pieces so the majority of it still located in acpi_early_init() >>> and the part switching over the platform into the ACPI mode goes into >>> a new function, acpi_subsystem_init(), executed at the original early >>> ACPI initialization spot. >>> >>> That fixes the Tyan S8812 boot problem, but still allows ACPI >>> tables to be loaded earlier which is useful to the EFI code in >>> efi_enter_virtual_mode(). >>> >>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=97141 >>> Fixes: 73f7d1ca3263 "ACPI / init: Run acpi_early_init() before timekeeping_init()" >>> Reported-and-tested-by: Marius Tolzmann >>> Signed-off-by: Rafael J. Wysocki >>> Acked-by: Toshi Kani >>> --- >>> drivers/acpi/bus.c | 56 +++++++++++++++++++++++++++++++++++++-------------- >>> include/linux/acpi.h | 2 + >>> init/main.c | 1 >>> 3 files changed, 44 insertions(+), 15 deletions(-) >>> >>> Index: linux-pm/drivers/acpi/bus.c >>> =================================================================== >>> --- linux-pm.orig/drivers/acpi/bus.c >>> +++ linux-pm/drivers/acpi/bus.c >>> @@ -470,6 +470,16 @@ static int __init acpi_bus_init_irq(void >>> return 0; >>> } >>> >>> +/** >>> + * acpi_early_init - Initialize ACPICA and populate the ACPI namespace. >>> + * >>> + * The ACPI tables are accessible after this, but the handling of events has not >> >> Maybe we need to explicitly say that it's DSDT/SSDT, because static >> tables such as FADT and MADT are accessible in the very early stage >> of boot (in setup_arch()). > > Well, it never says that none of the tables are accessible earlier. Ah, that makes sense :) Thanks Hanjun -- 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/