Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755198Ab1DDRzZ (ORCPT ); Mon, 4 Apr 2011 13:55:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57033 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754973Ab1DDRzY (ORCPT ); Mon, 4 Apr 2011 13:55:24 -0400 From: Matthew Garrett To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Matthew Garrett Subject: [PATCH] X86: Reorder reboot method preferences Date: Mon, 4 Apr 2011 13:55:05 -0400 Message-Id: <1301939705-2404-1-git-send-email-mjg@redhat.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 209.6.41.104 X-SA-Exim-Mail-From: mjg@redhat.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2500 Lines: 72 Windows reboots by hitting the ACPI reboot vector (if available), trying the keyboard controller, hitting the ACPI reboot vector again and then giving the keyboard controller one last go. This is important for modern hardware, which often lacks a keyboard controller and may even wedge if the legacy io ports are hit. Rework our reboot process a little to default to matching this behaviour, although we'll fall through to attempting a triple fault if nothing else works. Signed-off-by: Matthew Garrett --- arch/x86/kernel/reboot.c | 23 ++++++++++++++++++++++- 1 files changed, 22 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index d3ce37e..9dd4330 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -35,7 +35,7 @@ EXPORT_SYMBOL(pm_power_off); static const struct desc_ptr no_idt = {}; static int reboot_mode; -enum reboot_type reboot_type = BOOT_KBD; +enum reboot_type reboot_type = BOOT_ACPI; int reboot_force; #if defined(CONFIG_X86_32) && defined(CONFIG_SMP) @@ -477,9 +477,23 @@ void __attribute__((weak)) mach_reboot_fixups(void) { } +/* + * Windows does the following on reboot: + * 1) If the FADT has the ACPI reboot register flag set, try it + * 2) If still alive, write to the keyboard controller + * 3) If still alive, write to the ACPI reboot register again + * 4) If still alive, write to the keyboard controller again + * + * If the machine is still alive at this stage, it gives up. We default to + * following the same pattern, except that if we're still alive after (4) we'll + * try to force a triple fault and then cycle between hitting the keyboard + * controller and doing that + */ static void native_machine_emergency_restart(void) { int i; + int attempt = 0; + int orig_reboot_type = reboot_type; if (reboot_emergency) emergency_vmx_disable_all(); @@ -501,6 +515,13 @@ static void native_machine_emergency_restart(void) outb(0xfe, 0x64); /* pulse reset low */ udelay(50); } + if (attempt == 0 && orig_reboot_type == BOOT_ACPI) { + attempt = 1; + reboot_type = BOOT_ACPI; + } else { + reboot_type = BOOT_TRIPLE; + } + break; case BOOT_TRIPLE: load_idt(&no_idt); -- 1.7.4.1 -- 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/