2010-01-21 17:20:46

by Christian Hofstaedtler

[permalink] [raw]
Subject: [PATCH 1/2] x86: Unify reboot_type selection

Unify x86_32-only and x86_32+x86_64 reboot quirks selection functions,
so the code path is a bit easier to understand and gets a predefined
execution order.

Signed-off-by: Christian Hofstaedtler <[email protected]>
---
arch/x86/include/asm/emergency-restart.h | 1 +
arch/x86/kernel/reboot.c | 43 +++++++++++++++++++++---------
2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/emergency-restart.h b/arch/x86/include/asm/emergency-restart.h
index cc70c1c..72ee23a 100644
--- a/arch/x86/include/asm/emergency-restart.h
+++ b/arch/x86/include/asm/emergency-restart.h
@@ -2,6 +2,7 @@
#define _ASM_X86_EMERGENCY_RESTART_H

enum reboot_type {
+ BOOT_UNDECIDED = '?',
BOOT_TRIPLE = 't',
BOOT_KBD = 'k',
#ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 1545bc0..36f0c86 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -34,7 +34,7 @@ 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_UNDECIDED;
int reboot_force;

#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
@@ -134,7 +134,11 @@ static int __init set_bios_reboot(const struct dmi_system_id *d)
return 0;
}

-static struct dmi_system_id __initdata reboot_dmi_table[] = {
+/*
+ * This table only gets used on x86_32, so only use with
+ * set_bios_reboot.
+ */
+static struct dmi_system_id __initdata reboot_dmi_table_x86_32[] = {
{ /* Handle problems with rebooting on Dell E520's */
.callback = set_bios_reboot,
.ident = "Dell E520",
@@ -270,13 +274,6 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
{ }
};

-static int __init reboot_init(void)
-{
- dmi_check_system(reboot_dmi_table);
- return 0;
-}
-core_initcall(reboot_init);
-
/* The following code and data reboots the machine by switching to real
mode and jumping to the BIOS reset entry point, as if the CPU has
really been reset. The previous version asked the keyboard
@@ -427,7 +424,8 @@ static int __init set_pci_reboot(const struct dmi_system_id *d)
return 0;
}

-static struct dmi_system_id __initdata pci_reboot_dmi_table[] = {
+/* This table gets used on x86_32 AND x86_64. */
+static struct dmi_system_id __initdata reboot_dmi_table_all[] = {
{ /* Handle problems with rebooting on Apple MacBook5 */
.callback = set_pci_reboot,
.ident = "Apple MacBook5",
@@ -455,12 +453,30 @@ static struct dmi_system_id __initdata pci_reboot_dmi_table[] = {
{ }
};

-static int __init pci_reboot_init(void)
+/* Decide how we will reboot:
+ * - Check the X86_32-only quirks table.
+ * - Check the generic quirks table.
+ * - Default to old-style Keyboard Controller reboot.
+ */
+static int __init reboot_init(void)
{
- dmi_check_system(pci_reboot_dmi_table);
+ /* don't override user decisions (reboot=...) */
+ if (reboot_type != BOOT_UNDECIDED)
+ return 0;
+
+#ifdef CONFIG_X86_32
+ dmi_check_system(reboot_dmi_table_x86_32);
+#endif /* CONFIG_X86_32 */
+ dmi_check_system(reboot_dmi_table_all);
+
+ if (reboot_type != BOOT_UNDECIDED)
+ return 0;
+
+ reboot_type = BOOT_KBD;
+
return 0;
}
-core_initcall(pci_reboot_init);
+core_initcall(reboot_init);

static inline void kb_wait(void)
{
@@ -534,6 +550,7 @@ static void native_machine_emergency_restart(void)
for (;;) {
/* Could also try the reset bit in the Hammer NB */
switch (reboot_type) {
+ case BOOT_UNDECIDED:
case BOOT_KBD:
mach_reboot_fixups(); /* for board specific fixups */

--
1.6.4.4


2010-01-21 17:20:57

by Christian Hofstaedtler

[permalink] [raw]
Subject: [PATCH 2/2] Default to ACPI reboots on newish X86 hardware

Newer hardware reportedly can no longer successfully reboot using the
keyboard controller, but needs to use ACPI instead.

To not cause problems with older hardware, only hardware with a BIOS
date 2003 or newer is considered for this choice.
Broken BIOSes (no DMI BIOS date, or BIOS date of 0) also get ACPI
reboots, but those will auto fallback to KBD reboots, as ACPI won't get
enabled without acpi=force.
---
arch/x86/kernel/reboot.c | 32 ++++++++++++++++++++++++++++++--
1 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 36f0c86..919453a 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -453,10 +453,33 @@ static struct dmi_system_id __initdata reboot_dmi_table_all[] = {
{ }
};

+/* See if the Hardware is new enough to support ACPI reboots. */
+static int __init reboot_acpi_likey_supported(void)
+{
+ int year;
+
+ /* No BIOS date? We can safely say "Yes" here, because ACPI-reboot
+ * will only work when acpi=force was specified, else it falls back
+ * to KBD-reboots anyway. */
+ if (!dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL)) {
+ return 1;
+ }
+ if (year == 0) {
+ return 1;
+ }
+
+ /* 2003 was decided as the cut-off year. */
+ if (year < 2003) {
+ return 0;
+ }
+ return 1;
+}
+
/* Decide how we will reboot:
* - Check the X86_32-only quirks table.
* - Check the generic quirks table.
- * - Default to old-style Keyboard Controller reboot.
+ * - Check if we could use ACPI-based reboot.
+ * - Fall back to old-style Keyboard Controller reboot.
*/
static int __init reboot_init(void)
{
@@ -472,7 +495,12 @@ static int __init reboot_init(void)
if (reboot_type != BOOT_UNDECIDED)
return 0;

- reboot_type = BOOT_KBD;
+ if (reboot_acpi_likey_supported()) {
+ reboot_type = BOOT_ACPI;
+ } else {
+ printk(KERN_INFO "Selecting old-style reboot for older hardware\n");
+ reboot_type = BOOT_KBD;
+ }

return 0;
}
--
1.6.4.4

2010-01-21 18:33:46

by H. Peter Anvin

[permalink] [raw]
Subject: Re: [PATCH 1/2] x86: Unify reboot_type selection

On 01/21/2010 09:18 AM, Christian Hofstaedtler wrote:
> Unify x86_32-only and x86_32+x86_64 reboot quirks selection functions,
> so the code path is a bit easier to understand and gets a predefined
> execution order.

>
> -static struct dmi_system_id __initdata reboot_dmi_table[] = {
> +/*
> + * This table only gets used on x86_32, so only use with
> + * set_bios_reboot.
> + */
> +static struct dmi_system_id __initdata reboot_dmi_table_x86_32[] = {
> { /* Handle problems with rebooting on Dell E520's */
> .callback = set_bios_reboot,
> .ident = "Dell E520",
> @@ -270,13 +274,6 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
> { }
> };
>

I think it would make more sense to just #ifdef off a section of a
single table, instead of having an #ifdef for a separate table and an
#ifdef for a table entry.

I don't know how big these tables are -- this is initdata after all, so
unless the tables are really small, we could just make set_bios_reboot a
noop on x86-64.

-hpa

2010-01-23 19:57:47

by Len Brown

[permalink] [raw]
Subject: Re: [PATCH 2/2] Default to ACPI reboots on newish X86 hardware

Hi Christian,
I've replaced your previous patch in the acpi-test tree with this
refreshed pair.

Note that the 2nd patch had some checkpatch issues.
Perhaps you can run checkpatch before sending future patches.

WARNING: braces {} are not necessary for single statement blocks
#35: FILE: arch/x86/kernel/reboot.c:464:
+ if (!dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL)) {
+ return 1;
+ }

WARNING: braces {} are not necessary for single statement blocks
#38: FILE: arch/x86/kernel/reboot.c:467:
+ if (year == 0) {
+ return 1;
+ }

WARNING: braces {} are not necessary for single statement blocks
#43: FILE: arch/x86/kernel/reboot.c:472:
+ if (year < 2003) {
+ return 0;
+ }

ERROR: Missing Signed-off-by: line(s)

total: 1 errors, 3 warnings, 47 lines checked


thanks,
Len Brown, Intel Open Source Technology Center