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

PATCH In review Jeremy Fitzhardinge 2 participants 3 messages Jul 22, 2010 – Jul 23, 2010

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Jeremy Fitzhardinge

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#0 lore raw

PATCH 1/1 x86: Do not try to disable hpet if it hasn't been initialized before

[ x86 folk: While this patch is just a generic x86 bugfix, it really only affects
the Xen pv-on-hvm patch series that I'm going to post shortly. Do you want to commit it separately via tip.git, or are you OK with me sending it to Linus directly? - J ]

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 <[email protected]>
Acked-by Venkatesh Pallipadi <[email protected]>
arch/x86/kernel/hpet.c +10 -8
index a198b7c..9e90dac 100644
@@ -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
reviewer
#1 lore raw
Quoted 5 lines · Jeremy Fitzhardinge

[ x86 folk: While this patch is just a generic x86 bugfix, it really only affects
the Xen pv-on-hvm patch series that I'm going to post shortly. Do you want to commit it separately via tip.git, or are you OK with me sending it to Linus directly? - J ]

I think it would be best if we took it via tip:x86/urgent, if that is okay with you.

-hpa

author
#2 lore raw
Quoted 10 lines · H. Peter Anvin
Quoted 8 lines · Jeremy Fitzhardinge

[ x86 folk: While this patch is just a generic x86 bugfix, it really only affects
the Xen pv-on-hvm patch series that I'm going to post shortly. Do
you want to
commit it separately via tip.git, or are you OK with me sending it
to Linus
directly? - J ]

Quoted 2 lines

I think it would be best if we took it via tip:x86/urgent, if that is okay with you.

Sure.

Thanks,
J