[PATCH] x86: Do not try to disable hpet if it hasn't been initialized before

[PATCH] x86: Do not try to disable hpet if it hasn't been initialized before

[Stefano Stabellini]

hpet_disable is called unconditionally on machine reboot if hpet support
is compiled in the kernel.
hpet_disable only checks if the machine is hpet capable but doesn't make
sure that hpet has been initialized.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
---
 arch/x86/kernel/hpet.c |   18 ++++++++++--------
 1 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index a198b7c..9e90dac 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -964,16 +964,18 @@ fs_initcall(hpet_late_init);
 
 void hpet_disable(void)
 {
-	if (is_hpet_capable()) {
-		unsigned int cfg = hpet_readl(HPET_CFG);
+	unsigned int cfg;
 
-		if (hpet_legacy_int_enabled) {
-			cfg &= ~HPET_CFG_LEGACY;
-			hpet_legacy_int_enabled = 0;
-		}
-		cfg &= ~HPET_CFG_ENABLE;
-		hpet_writel(cfg, HPET_CFG);
+	if (!is_hpet_capable() || !hpet_address || !hpet_virt_address)
+		return;
+
+	cfg = hpet_readl(HPET_CFG);
+	if (hpet_legacy_int_enabled) {
+		cfg &= ~HPET_CFG_LEGACY;
+		hpet_legacy_int_enabled = 0;
 	}
+	cfg &= ~HPET_CFG_ENABLE;
+	hpet_writel(cfg, HPET_CFG);
 }
 
 #ifdef CONFIG_HPET_EMULATE_RTC
-- 
1.7.0.4

[tip:x86/urgent] x86: Do not try to disable hpet if it hasn't been initialized before

[tip-bot for Stefano Stabellini]

Commit-ID:  ff4878089e1eaeac79d57878ad4ea32910fb4037
Gitweb:     http://git.kernel.org/tip/ff4878089e1eaeac79d57878ad4ea32910fb4037
Author:     Stefano Stabellini <stefano.stabellini@eu.citrix.com>
AuthorDate: Wed, 21 Jul 2010 18:32:37 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 23 Jul 2010 12:53:00 +0200

x86: Do not try to disable hpet if it hasn't been initialized before

hpet_disable is called unconditionally on machine reboot if hpet support
is compiled in the kernel.
hpet_disable only checks if the machine is hpet capable but doesn't make
sure that hpet has been initialized.

[ tglx: Made it a one liner and removed the redundant hpet_address check ]

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
LKML-Reference: <alpine.DEB.2.00.1007211726240.22235@kaball-desktop>
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/hpet.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index a198b7c..ba390d7 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -964,7 +964,7 @@ fs_initcall(hpet_late_init);
 
 void hpet_disable(void)
 {
-	if (is_hpet_capable()) {
+	if (is_hpet_capable() && hpet_virt_address) {
 		unsigned int cfg = hpet_readl(HPET_CFG);
 
 		if (hpet_legacy_int_enabled) {