PM: introduce set_target method in pm_ops

Commit 52ade9b3b97fd3bea42842a056fe0786c28d0555 changed the suspend code
ordering to execute pm_ops->prepare() after the device model per-device
.suspend() calls in order to fix some ACPI-related issues.  Unfortunately, it
broke the at91 platform which assumed that pm_ops->prepare() would be called
before suspending devices.

at91 used pm_ops->prepare() to get notified of the target system sleep state,
so that it could use this information while suspending devices.  However, with
the current suspend code ordering pm_ops->prepare() is called too late for
this purpose.  Thus, at91 needs an additional method in 'struct pm_ops' that
will be used for notifying the platform of the target system sleep state.
Moreover, in the future such a method will also be needed by ACPI.

This patch adds the .set_target() method to 'struct pm_ops' and makes the
suspend code call it, if implemented, before executing the device model
per-device .suspend() calls.  It also modifies the at91 code to use
pm_ops->set_target() instead of pm_ops->prepare().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 8812985f3029..fc45ed22620f 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -15,7 +15,6 @@
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/init.h>
-#include <linux/pm.h>
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/resume-trace.h>
@@ -97,6 +96,11 @@ static int suspend_prepare(suspend_state_t state)
                 }
         }
 
+        if (pm_ops->set_target) {
+                error = pm_ops->set_target(state);
+                if (error)
+                        goto Thaw;
+        }
         suspend_console();
         error = device_suspend(PMSG_SUSPEND);
         if (error) {