From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286AbbCDGFG (ORCPT ); Wed, 4 Mar 2015 01:05:06 -0500 Received: from mga09.intel.com ([134.134.136.24]:7023 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752665AbbCDGFE (ORCPT ); Wed, 4 Mar 2015 01:05:04 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,685,1418112000"; d="scan'208";a="686580484" Message-ID: <54F6A08B.2010105@linux.intel.com> Date: Wed, 04 Mar 2015 14:04:59 +0800 From: "Li, Aubrey" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Ingo Molnar CC: "alan@linux.intel.com" , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , arjan@linux.intel.com, "Rafael J. Wysocki" , Len.Brown@intel.com, x86@kernel.org, LKML , Borislav Petkov Subject: Re: [PATCH] x86: Bypass legacy PIC and PIT on ACPI hardware reduced platform References: <54F67ACC.3010500@linux.intel.com> <20150304050858.GB5158@gmail.com> <54F69774.2050400@linux.intel.com> <20150304053106.GA3701@gmail.com> In-Reply-To: <20150304053106.GA3701@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/3/4 13:31, Ingo Molnar wrote: > > * Li, Aubrey wrote: > >> On 2015/3/4 13:08, Ingo Molnar wrote: >>> >>> * Li, Aubrey wrote: >>> >>>> On ACPI hardware reduced platform, the legacy PIC and PIT may not be >>>> initialized even though they may be present in silicon. Touching >>>> these legacy components causes unexpected result on system. >>>> >>>> On Bay Trail-T(ASUS-T100) platform, touching these legacy components >>>> blocks platform hardware low idle power state(S0ix) during system suspend. >>>> So we should bypass them on ACPI hardware reduced platform. >>>> >>>> Suggested-by: Arjan van de Ven >>>> Signed-off-by: Li Aubrey >>>> Cc: Len Brown >>>> Cc: Rafael J. Wysocki >>>> --- >>>> arch/x86/kernel/irqinit.c | 6 +++++- >>>> arch/x86/kernel/time.c | 3 ++- >>>> 2 files changed, 7 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c >>>> index 70e181e..9a64cc3 100644 >>>> --- a/arch/x86/kernel/irqinit.c >>>> +++ b/arch/x86/kernel/irqinit.c >>>> @@ -75,7 +75,11 @@ void __init init_ISA_irqs(void) >>>> #if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC) >>>> init_bsp_APIC(); >>>> #endif >>>> - legacy_pic->init(0); >>>> + if (acpi_gbl_reduced_hardware) { >>>> + pr_info("Using NULL legacy PIC\n"); >>>> + legacy_pic = &null_legacy_pic; >>>> + } else >>>> + legacy_pic->init(0); >>>> >>>> for (i = 0; i < nr_legacy_irqs(); i++) >>>> irq_set_chip_and_handler(i, chip, handle_level_irq); >>>> diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c >>>> index 25adc0e..5ba94fa 100644 >>>> --- a/arch/x86/kernel/time.c >>>> +++ b/arch/x86/kernel/time.c >>>> @@ -14,6 +14,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> >>>> #include >>>> #include >>>> @@ -76,7 +77,7 @@ void __init setup_default_timer_irq(void) >>>> /* Default timer init function */ >>>> void __init hpet_time_init(void) >>>> { >>>> - if (!hpet_enable()) >>>> + if (!hpet_enable() && !acpi_gbl_reduced_hardware) >>>> setup_pit_timer(); >>>> setup_default_timer_irq(); >>>> } >>> >>> So the whole acpi_gbl_reduced_hardware flaggery sucks as it mixes >>> various hardware drivers that have little relation to each other... >>> >>> Instead of having a proper platform init this flag hooks into various >>> drivers and generic code, such as the efi reboot and shutdown code, >>> and now the generic irq init code. >>> >>> For this IRQ init problem, why not add a proper callback to >>> x86_platform_ops, define your own IRQ init function, initialize it in >>> your platform init sequence and let it be called? That solves it >>> without creating an ugly mix of different platform methods. >>> >>> For the EFI shutdown case, what's wrong with setting your own >>> pm_power_off handler like most of the other platforms are doing? Plus >>> the EFI code in drivers/firmware/efi/reboot.c should probably only set >>> the shutdown handler if pm_power_off is still NULL. >> >> I think our goal is to make the code as generic as possible for all >> x86 platform, rather than creating a new x86 branch, I added Alan >> Cox for this strategy discussion. >> >> Do you have any inputs for the patch itself? > > Other than that the patch is unacceptable for an upstream merge in its > current form for the reason I mentioned? No. So you are suggesting we extend a new x86 platform branch and override the x86_platform and pm_power_off and reboot, like what intel_mid does? Thanks, -Aubrey > > Thanks, > > Ingo > -- > 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/ > >