From: fwu@marvell.com (Fan Wu)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM:CPUIDLE: Fix wrongly used idle control counter
Date: Thu, 27 Sep 2012 14:36:01 +0800 [thread overview]
Message-ID: <1348727761-16485-1-git-send-email-fwu@marvell.com> (raw)
From: fwu <fwu@marvell.com>
1. On ARM platform, "nohlt" can be used to prevent core from idle
process, returning immediately.
2. There are two interface, exported for other modules, named
disable_hlt and enable_hlt and used to enable/disable the
cpuidle mechanism by increasing/decreasing "hlt_counter".
So, the more "hlt_counter" is, the more user want to disable
cpuidle. Disable_hlt and enable_hlt are paired operation,
when you first call disable_hlt and then enable_hlt, the
semantics are right, but if you call enable_hlt and
then disable_hlt, it is wrong.
3. Change "hlt_counter > 0" can fix the problem.
The judgement whethere the cpuidle is disabled need to check
whether the "hlt_counter > 0" rather than "hlt_counter != 0".
Change-Id: Ibd5ea805b0c01fe326833d333ce5d72e0447430a
Signed-off-by: fwu <fwu@marvell.com>
Signed-off-by: YiLu Mao <ylmao@marvell.com>
Signed-off-by: Ning Jiang <ning.jiang@marvell.com>
---
arch/arm/kernel/process.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 693b744..4dc2fee 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -204,7 +204,7 @@ void cpu_idle(void)
#ifdef CONFIG_PL310_ERRATA_769419
wmb();
#endif
- if (hlt_counter) {
+ if (hlt_counter > 0) {
local_irq_enable();
cpu_relax();
} else if (!need_resched()) {
--
1.7.0.4
next reply other threads:[~2012-09-27 6:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 6:36 Fan Wu [this message]
2012-09-27 8:53 ` [PATCH] ARM:CPUIDLE: Fix wrongly used idle control counter Russell King - ARM Linux
2012-09-27 9:19 ` Fan Wu
2012-09-27 9:50 ` Russell King - ARM Linux
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