[Xen-devel] [PATCH 10/12] Do not try to disable hpet if it hasn't been initialized before

[stefano.stabellini@xxxxxxxxxxxxx]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
---
 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 23b4ecd..2b299da 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -959,16 +959,18 @@ 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


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