[PATCH] cpufreq: return EEXIST instead of EBUSY for second registering

[Yinghai Lu <yinghai@kernel.org>]

System that cpu support intel_pstate, acpi_cpufreq fail to
load, and udev keep trying until trace get filled up and
kernel crash.

The root cause is driver return ret from cpufreq_register_driver
and when some other driver take over before, it would return
EBUSY, then udev will keep trying...

cpufreq_register_driver should return EEXIST instead.
then system could boot without appending intel_pstate=disable
and still use intel_pstate.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/cpufreq/cpufreq.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-2.6.orig/drivers/cpufreq/cpufreq.c
+++ linux-2.6/drivers/cpufreq/cpufreq.c
@@ -2104,7 +2104,7 @@ int cpufreq_register_driver(struct cpufr
 	write_lock_irqsave(&cpufreq_driver_lock, flags);
 	if (cpufreq_driver) {
 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		return -EBUSY;
+		return -EEXIST;
 	}
 	cpufreq_driver = driver_data;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);