[PATCH] x86: Don't use MWAIT on AMD Family 10

It doesn't put the CPU into deeper sleep states, so it's better to use the standard
idle loop to save power. But allow to reenable it anyways for benchmarking.

I also removed the obsolete idle=halt on i386

Cc: andreas.herrmann@amd.com

Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 7 insertions, 5 deletions

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index d8d5ccc245c8..4f21765078b7 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -288,16 +288,18 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 
 static int __init idle_setup (char *str)
 {
-        if (!strncmp(str, "poll", 4)) {
+        if (!strcmp(str, "poll")) {
                 printk("using polling idle threads.\n");
                 pm_idle = poll_idle;
-        }
+        } else if (!strcmp(str, "mwait"))
+                force_mwait = 1;
+        else
+                return -1;
 
         boot_option_idle_override = 1;
-        return 1;
+        return 0;
 }
-
-__setup("idle=", idle_setup);
+early_param("idle", idle_setup);
 
 /* Prints also some state that isn't saved in the pt_regs */ 
 void __show_regs(struct pt_regs * regs)