On Fri, 2008-01-04 at 01:04 +0800, Rafael J. Wysocki wrote:
> On Thursday, 3 of January 2008, Shaohua Li wrote:
> >
> > On Wed, 2008-01-02 at 22:05 +0800, Rafael J. Wysocki wrote:
> > > On Wednesday, 2 of January 2008, Shaohua Li wrote:
> > > > ACPI defines a hardware signature. BIOS calculates the signature
> > > > according to hardware configure, if hardware changes, the
> signature
> > > will
> > > > change, in this case, S4 resume should fail.
> > >
> > > The idea is fine, but I'd prefer to do that in a more
> straightforward
> > > way.
> > > Namely, we can just:
> > > * write the signature into a variable in, for example,
> > > acpi_hibernation_prepare() (then, the "old" signature value will
> be
> > > automatically saved in the image)
> > > * compare it with a the "new" value read from the BIOS in
> > > acpi_hibernation_leave() and panic if there's a mismatch
> > > * add a configuration option to disable this behavior (just in
> case)
> > > This way we can avoid modifying the entire generic interface to
> add
> > > the feature
> > > specific to ACPI.
> > it would be better we do the check in boot kernel.
> Franky, I think we should also check in the image kernel, in case the
> boot
> one doesn't support ACPI as I said.
Ok, makes sense. I changed to check the signature in .higberation_leave
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
---
drivers/acpi/sleep/main.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
Index: linux/drivers/acpi/sleep/main.c
===================================================================
--- linux.orig/drivers/acpi/sleep/main.c 2008-01-03 13:37:08.000000000 +0800
+++ linux/drivers/acpi/sleep/main.c 2008-01-04 13:36:10.000000000 +0800
@@ -256,6 +256,17 @@ static int acpi_hibernation_enter(void)
return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}
+static unsigned long s4_hardware_signature;
+static struct acpi_table_facs *facs;
+static int nosigcheck;
+
+static int __init acpi_s4_nosigcheck(char *str)
+{
+ nosigcheck = 1;
+ return 1;
+}
+__setup("acpi_s4_nosigcheck", acpi_s4_nosigcheck);
+
static void acpi_hibernation_leave(void)
{
/*
@@ -263,6 +274,11 @@ static void acpi_hibernation_leave(void)
* enable it here.
*/
acpi_enable();
+ if (facs && s4_hardware_signature != facs->hardware_signature) {
+ printk(KERN_EMERG"PM: Hardware changed in the S4 circle, can't resume\n");
+ if (!nosigcheck)
+ panic("S4 resume error");
+ }
}
static void acpi_hibernation_finish(void)
@@ -449,6 +465,10 @@ int __init acpi_sleep_init(void)
sleep_states[ACPI_STATE_S4] = 1;
printk(" S4");
}
+ 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);
if (ACPI_SUCCESS(status)) {
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