From 3a53396b0381ec9d5180fd8fe7a681c8ce95fd9a Mon Sep 17 00:00:00 2001 From: ShuoX Liu Date: Wed, 28 Mar 2012 15:19:11 -0700 Subject: cpuidle: add a sysfs entry to disable specific C state for debug purpose. Some C states of new CPU might be not good. One reason is BIOS might configure them incorrectly. To help developers root cause it quickly, the patch adds a new sysfs entry, so developers could disable specific C state manually. In addition, C state might have much impact on performance tuning, as it takes much time to enter/exit C states, which might delay interrupt processing. With the new debug option, developers could check if a deep C state could impact performance and how much impact it could cause. Also add this option in Documentation/cpuidle/sysfs.txt. [akpm@linux-foundation.org: check kstrtol return value] Signed-off-by: ShuoX Liu Reviewed-by: Yanmin Zhang Reviewed-and-Tested-by: Deepthi Dharwar Signed-off-by: Andrew Morton Signed-off-by: Len Brown --- drivers/cpuidle/cpuidle.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/cpuidle/cpuidle.c') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 4869b5500234..77304b6b8aef 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -245,6 +245,7 @@ static void poll_idle_init(struct cpuidle_driver *drv) state->power_usage = -1; state->flags = 0; state->enter = poll_idle; + state->disable = 0; } #else static void poll_idle_init(struct cpuidle_driver *drv) {} -- cgit v1.2.3