From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754280AbbCDFbN (ORCPT ); Wed, 4 Mar 2015 00:31:13 -0500 Received: from mail-we0-f182.google.com ([74.125.82.182]:46952 "EHLO mail-we0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750917AbbCDFbM (ORCPT ); Wed, 4 Mar 2015 00:31:12 -0500 Date: Wed, 4 Mar 2015 06:31:06 +0100 From: Ingo Molnar To: "Li, Aubrey" 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 Message-ID: <20150304053106.GA3701@gmail.com> References: <54F67ACC.3010500@linux.intel.com> <20150304050858.GB5158@gmail.com> <54F69774.2050400@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54F69774.2050400@linux.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * 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. Thanks, Ingo