[PATCH 15/15] Revert "x86: default to reboot via ACPI"

Ingo Molnar mingo at elte.hu
Thu Nov 6 10:06:10 EST 2008

* Ingo Molnar <mingo at elte.hu> wrote:

> > Andrey Borzenkov's patch, for example, adds a new DMI entry 
> > because reboot=acpi breaks his keyboard (even without KVM, I 
> > guess). Andrey, was that the case?
> hm, IIRC the problem was KVM in his case too.

actually, Andrey's problem seems to be unrelated. So i've queued up 
the revert below in tip/x86/urgent for v2.6.28. Thanks guys!


>From 8d00450d296dedec9ada38d43b83e79cca6fd5a3 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost at redhat.com>
Date: Tue, 4 Nov 2008 12:52:44 -0200
Subject: [PATCH] Revert "x86: default to reboot via ACPI"

This reverts commit c7ffa6c26277b403920e2255d10df849bd613380.

the assumptio of this change was that this would not break
any existing machine. Andrey Borzenkov reported troubles with
the ACPI reboot method: the system would hang on reboot, necessiating
a power cycle. Probably more systems are affected as well.

Also, there are patches queued up for v2.6.29 to disable virtualization
on emergency_restart() - which was the original motivation of
this change.

Reported-by: Andrey Borzenkov <arvidjaar at mail.ru>
Bisected-by: Andrey Borzenkov <arvidjaar at mail.ru>
Signed-off-by: Eduardo Habkost <ehabkost at redhat.com>
Acked-by: Avi Kivity <avi at redhat.com>
Signed-off-by: Ingo Molnar <mingo at elte.hu>
 arch/x86/kernel/reboot.c |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index f4c93f1..724adfc 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -29,11 +29,7 @@ EXPORT_SYMBOL(pm_power_off);
 static const struct desc_ptr no_idt = {};
 static int reboot_mode;
- * Keyboard reset and triple fault may result in INIT, not RESET, which
- * doesn't work when we're in vmx root mode.  Try ACPI first.
- */
-enum reboot_type reboot_type = BOOT_ACPI;
+enum reboot_type reboot_type = BOOT_KBD;
 int reboot_force;
 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)

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