[PATCH] PowerMac: force only suspend-to-disk to be valid

For a very long time, echoing 'standby' or 'mem' into /sys/power/state has
killed the machine on powerpc.  This patch fixes that.

This patch adds the .valid callback to pm_ops on PowerMac so that only the
suspend to disk state can be entered.  Note that just returning 0 would
suffice since the upper layers don't pass PM_SUSPEND_DISK down, but we
handle it there regardless just in case that changes.

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 4d15e396655c..b9200fb07815 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -463,11 +463,23 @@ static int pmac_pm_finish(suspend_state_t state)
         return 0;
 }
 
+static int pmac_pm_valid(suspend_state_t state)
+{
+        switch (state) {
+        case PM_SUSPEND_DISK:
+                return 1;
+        /* can't do any other states via generic mechanism yet */
+        default:
+                return 0;
+        }
+}
+
 static struct pm_ops pmac_pm_ops = {
         .pm_disk_mode   = PM_DISK_SHUTDOWN,
         .prepare        = pmac_pm_prepare,
         .enter          = pmac_pm_enter,
         .finish         = pmac_pm_finish,
+        .valid          = pmac_pm_valid,
 };
 
 #endif /* CONFIG_SOFTWARE_SUSPEND */