aboutsummaryrefslogtreecommitdiff
path: root/drivers/acpi
diff options
context:
space:
mode:
authorShaohua Li <shaohua.li@intel.com>2008-07-23 21:28:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:24 -0700
commitbdfe6b7c681669148dae4db27eb24ee5408ba371 (patch)
tree644b84a7e4a329a635d9a9bc02102424cfb616e2 /drivers/acpi
parent2f15fc4bdf91eb399da3f47a09c55831d9f22826 (diff)
pm: acpi hibernation: utilize hardware signature
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. [shaohua.li@intel.com: build fix] Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Andi Kleen <andi@firstfloor.org> Cc: Len Brown <lenb@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: <Valdis.Kletnieks@vt.edu> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/sleep/main.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index 0489a7d1d42..313507accf1 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -283,6 +283,15 @@ static struct platform_suspend_ops acpi_suspend_ops_old = {
#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;
@@ -316,6 +325,12 @@ 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_pm_enable_gpes(void)
@@ -544,6 +559,13 @@ int __init acpi_sleep_init(void)
&acpi_hibernation_ops_old : &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);