From: Shaohua Li <shaohua.li@xxxxxxxxx>
ACPI defines a hardware signature. BIOS calculates the signature
according to hardware configure and if hardware changes while
hibernated, the signature will change. In that case, S4 resume
should fail.
Still, there may be systems on which this mechanism does not work
correctly, so it is better to provide a workaround for them. For
this reason, add a new switch to the acpi_sleep= command line
argument allowing one to disable hardware signature checking.
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
Documentation/kernel-parameters.txt | 4 +++-
arch/x86/kernel/acpi/sleep.c | 2 ++
drivers/acpi/sleep/main.c | 22 ++++++++++++++++++++++
include/linux/acpi.h | 3 +++
4 files changed, 30 insertions(+), 1 deletion(-)
Index: linux-2.6/drivers/acpi/sleep/main.c
===================================================================
--- linux-2.6.orig/drivers/acpi/sleep/main.c
+++ linux-2.6/drivers/acpi/sleep/main.c
@@ -255,6 +255,15 @@ static struct dmi_system_id __initdata a
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
+static unsigned long s4_hardware_signature;
+static struct acpi_table_facs *facs;
+static bool nosigcheck;
+
+void __init acpi_no_s4_hw_signature(void)
+{
+ nosigcheck = true;
+}
+
static int acpi_hibernation_begin(void)
{
acpi_target_sleep_state = ACPI_STATE_S4;
@@ -301,6 +310,12 @@ static void acpi_hibernation_leave(void)
acpi_enable();
/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(ACPI_STATE_S4);
+ /* Check the hardware signature */
+ if (facs && s4_hardware_signature != facs->hardware_signature) {
+ printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
+ "cannot resume!\n");
+ panic("ACPI S4 hardware signature mismatch");
+ }
}
static void acpi_hibernation_finish(void)
@@ -501,6 +516,13 @@ int __init acpi_sleep_init(void)
hibernation_set_ops(&acpi_hibernation_ops);
sleep_states[ACPI_STATE_S4] = 1;
printk(" S4");
+ if (!nosigcheck) {
+ acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
+ (struct acpi_table_header **)&facs);
+ if (facs)
+ s4_hardware_signature =
+ facs->hardware_signature;
+ }
}
#endif
status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -147,10 +147,12 @@ and is between 256 and 4096 characters.
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep }
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig }
See Documentation/power/video.txt for s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
+ s4_nohwsig prevents ACPI hardware signature from being
+ used during resume from hibernation.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
Index: linux-2.6/arch/x86/kernel/acpi/sleep.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/acpi/sleep.c
+++ linux-2.6/arch/x86/kernel/acpi/sleep.c
@@ -124,6 +124,8 @@ static int __init acpi_sleep_setup(char
acpi_realmode_flags |= 2;
if (strncmp(str, "s3_beep", 7) == 0)
acpi_realmode_flags |= 4;
+ if (strncmp(str, "s4_nohwsig", 10) == 0)
+ acpi_no_s4_hw_signature();
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
Index: linux-2.6/include/linux/acpi.h
===================================================================
--- linux-2.6.orig/include/linux/acpi.h
+++ linux-2.6/include/linux/acpi.h
@@ -234,6 +234,9 @@ int acpi_check_region(resource_size_t st
int acpi_check_mem_region(resource_size_t start, resource_size_t n,
const char *name);
+#ifdef CONFIG_PM_SLEEP
+void __init acpi_no_s4_hw_signature(void);
+#endif /* CONFIG_PM_SLEEP */
#else /* CONFIG_ACPI */
static inline int early_acpi_boot_init(void)
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