diff options
| -rw-r--r-- | arch/x86/kernel/hpet.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 801497a16e0e..73deaffadd03 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -278,6 +278,13 @@ static int hpet_legacy_next_event(unsigned long delta, cnt += (u32) delta; hpet_writel(cnt, HPET_T0_CMP); + /* + * We need to read back the CMP register to make sure that + * what we wrote hit the chip before we compare it to the + * counter. + */ + WARN_ON((u32)hpet_readl(HPET_T0_CMP) != cnt); + return (s32)((u32)hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0; } |