[GIT PULL] x86/reboot change for v2.6.40

From: Ingo Molnar
Date: Thu May 19 2011 - 17:20:59 EST


Linus,

Please pull the latest x86-reboot-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git x86-reboot-for-linus

This change modifies the x86 reboot method order to be ACPI first.

This affects a lot of systems - the hope is that it will reduce the steady
influx of reboot quirks (and the large body of boxes that will not reboot
properly under Linux).

Thanks,

Ingo

------------------>
Matthew Garrett (1):
x86: Reorder reboot method preferences


arch/x86/kernel/reboot.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 08c44b0..0c016f7 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -36,7 +36,7 @@ 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)
@@ -478,9 +478,24 @@ void __attribute__((weak)) mach_reboot_fixups(void)
{
}

+/*
+ * Windows compatible x86 hardware expects 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();
@@ -502,6 +517,13 @@ 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);
--
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