Hibernation: Enter platform hibernation state in a consistent way

Make hibernation_platform_enter() execute the enter-a-sleep-state sequence
instead of the mixed shutdown-with-entering-S4 thing.

Replace the shutting down of devices done by kernel_shutdown_prepare(), before
entering the ACPI S4 sleep state, with suspending them and the shutting down
of sysdevs with calling device_power_down(PMSG_SUSPEND) (just like before
entering S1 or S3, but the target state is now S4).   Also, disable the
nonboot CPUs before entering the sleep state (S4), which generally always is a
good idea.

This is known to fix the "double disk spin down during hibernation" on some
machines, eg.  HPC nx6325 (ref.  http://lkml.org/lkml/2007/8/7/316 and the
following thread).   Moreover, it has been reported to make
/sys/class/rtc/rtc0/wakealarm work correctly with hibernation for some users.
It also generally causes the hibernation state (ACPI S4) to be entered faster.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index e50f4da..8b15f77 100644 (file)
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -278,21 +278,50 @@ int hibernation_platform_enter(void)
 {
        int error;
 
-       if (hibernation_ops) {
-               kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
-               /*
-                * We have cancelled the power transition by running
-                * hibernation_ops->finish() before saving the image, so we
-                * should let the firmware know that we're going to enter the
-                * sleep state after all
-                */
-               error = hibernation_ops->prepare();
-               sysdev_shutdown();
-               if (!error)
-                       error = hibernation_ops->enter();
-       } else {
-               error = -ENOSYS;
+       if (!hibernation_ops)
+               return -ENOSYS;
+
+       /*
+        * We have cancelled the power transition by running
+        * hibernation_ops->finish() before saving the image, so we should let
+        * the firmware know that we're going to enter the sleep state after all
+        */
+       error = hibernation_ops->start();
+       if (error)
+               return error;
+
+       suspend_console();
+       error = device_suspend(PMSG_SUSPEND);
+       if (error)
+               goto Resume_console;
+
+       error = hibernation_ops->prepare();
+       if (error)
+               goto Resume_devices;
+
+       error = disable_nonboot_cpus();
+       if (error)
+               goto Finish;
+
+       local_irq_disable();
+       error = device_power_down(PMSG_SUSPEND);
+       if (!error) {
+               hibernation_ops->enter();
+               /* We should never get here */
+               while (1);
        }
+       local_irq_enable();
+
+       /*
+        * We don't need to reenable the nonboot CPUs or resume consoles, since
+        * the system is going to be halted anyway.
+        */
+ Finish:
+       hibernation_ops->finish();
+ Resume_devices:
+       device_resume();
+ Resume_console:
+       resume_console();
        return error;
 }
 
@@ -309,14 +338,14 @@ static void power_down(void)
        case HIBERNATION_TEST:
        case HIBERNATION_TESTPROC:
                break;
-       case HIBERNATION_SHUTDOWN:
-               kernel_power_off();
-               break;
        case HIBERNATION_REBOOT:
                kernel_restart(NULL);
                break;
        case HIBERNATION_PLATFORM:
                hibernation_platform_enter();
+       case HIBERNATION_SHUTDOWN:
+               kernel_power_off();
+               break;
        }
        kernel_halt();
        /*