From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758043AbbCDDYC (ORCPT ); Tue, 3 Mar 2015 22:24:02 -0500 Received: from mga01.intel.com ([192.55.52.88]:7957 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756737AbbCDDYA (ORCPT ); Tue, 3 Mar 2015 22:24:00 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,685,1418112000"; d="scan'208";a="535756039" Message-ID: <54F67ACC.3010500@linux.intel.com> Date: Wed, 04 Mar 2015 11:23:56 +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: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar CC: arjan@linux.intel.com, "Rafael J. Wysocki" , Len.Brown@intel.com, x86@kernel.org, LKML Subject: [PATCH] x86: Bypass legacy PIC and PIT on ACPI hardware reduced platform 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 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(); } -- 1.9.1