Introduce a governor rating scheme to pick the right governor by default.

Signed-off-by: Venkatesh Pallipadi <[EMAIL PROTECTED]>

Index: linux-2.6.22-rc-mm/include/linux/cpuidle.h
===================================================================
--- linux-2.6.22-rc-mm.orig/include/linux/cpuidle.h     2007-06-05 
17:00:09.000000000 -0700
+++ linux-2.6.22-rc-mm/include/linux/cpuidle.h  2007-06-05 17:01:08.000000000 
-0700
@@ -159,6 +159,7 @@
 struct cpuidle_governor {
        char                    name[CPUIDLE_NAME_LEN];
        struct list_head        governor_list;
+       unsigned int            rating;
 
        int  (*init)            (struct cpuidle_device *dev);
        void (*exit)            (struct cpuidle_device *dev);
Index: linux-2.6.22-rc-mm/drivers/cpuidle/governors/menu.c
===================================================================
--- linux-2.6.22-rc-mm.orig/drivers/cpuidle/governors/menu.c    2007-06-05 
15:46:34.000000000 -0700
+++ linux-2.6.22-rc-mm/drivers/cpuidle/governors/menu.c 2007-06-05 
17:04:32.000000000 -0700
@@ -153,6 +153,7 @@
 
 struct cpuidle_governor menu_governor = {
        .name =         "menu",
+       .rating =       20,
        .scan =         menu_scan_device,
        .select =       menu_select,
        .reflect =      menu_reflect,
Index: linux-2.6.22-rc-mm/drivers/cpuidle/governor.c
===================================================================
--- linux-2.6.22-rc-mm.orig/drivers/cpuidle/governor.c  2007-06-01 
16:25:49.000000000 -0700
+++ linux-2.6.22-rc-mm/drivers/cpuidle/governor.c       2007-06-05 
17:15:05.000000000 -0700
@@ -131,7 +131,8 @@
        if (__cpuidle_find_governor(gov->name) == NULL) {
                ret = 0;
                list_add_tail(&gov->governor_list, &cpuidle_governors);
-               if (!cpuidle_curr_governor)
+               if (!cpuidle_curr_governor ||
+                   cpuidle_curr_governor->rating < gov->rating)
                        cpuidle_switch_governor(gov);
        }
        mutex_unlock(&cpuidle_lock);
@@ -142,6 +143,29 @@
 EXPORT_SYMBOL_GPL(cpuidle_register_governor);
 
 /**
+ * cpuidle_replace_governor - find a replacement governor
+ * @exclude_rating: the rating that will be skipped while looking for
+ * new governor.
+ */
+struct cpuidle_governor *cpuidle_replace_governor(int exclude_rating)
+{
+       struct cpuidle_governor *gov;
+       struct cpuidle_governor *ret_gov = NULL;
+       unsigned int max_rating = 0;
+
+       list_for_each_entry(gov, &cpuidle_governors, governor_list) {
+               if (gov->rating == exclude_rating)
+                       continue;
+               if (gov->rating > max_rating) {
+                       max_rating = gov->rating;
+                       ret_gov = gov;
+               }
+       }
+
+       return ret_gov;
+}
+
+/**
  * cpuidle_unregister_governor - unregisters a governor
  * @gov: the governor
  */
@@ -151,8 +175,11 @@
                return;
 
        mutex_lock(&cpuidle_lock);
-       if (gov == cpuidle_curr_governor)
-               cpuidle_switch_governor(NULL);
+       if (gov == cpuidle_curr_governor) {
+               struct cpuidle_governor *new_gov;
+               new_gov = cpuidle_replace_governor(gov->rating);
+               cpuidle_switch_governor(new_gov);
+       }
        list_del(&gov->governor_list);
        mutex_unlock(&cpuidle_lock);
 }
Index: linux-2.6.22-rc-mm/drivers/cpuidle/governors/ladder.c
===================================================================
--- linux-2.6.22-rc-mm.orig/drivers/cpuidle/governors/ladder.c  2007-06-01 
16:25:49.000000000 -0700
+++ linux-2.6.22-rc-mm/drivers/cpuidle/governors/ladder.c       2007-06-05 
17:03:37.000000000 -0700
@@ -199,6 +199,7 @@
 
 static struct cpuidle_governor ladder_governor = {
        .name =         "ladder",
+       .rating =       10,
        .init =         ladder_init_device,
        .exit =         ladder_exit_device,
        .scan =         ladder_scan_device,
-
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