On Thu, 01 Feb 2007 10:59:53 +0100 [EMAIL PROTECTED] wrote:

> Fix a race in the initialization of HPET, which might result in a 
> 5 minute lockup on boot.
> 

What race?  Please always describe bugs when fixing them.

> 
> Index: linux-2.6.20-rc5/arch/x86_64/kernel/apic.c
> ===================================================================
> --- linux-2.6.20-rc5.orig/arch/x86_64/kernel/apic.c
> +++ linux-2.6.20-rc5/arch/x86_64/kernel/apic.c
> @@ -764,10 +767,12 @@ static void setup_APIC_timer(unsigned in
>  
>       /* wait for irq slice */
>       if (vxtime.hpet_address && hpet_use_timer) {
> -             int trigger = hpet_readl(HPET_T0_CMP);
> -             while (hpet_readl(HPET_COUNTER) >= trigger)
> -                     /* do nothing */ ;
> -             while (hpet_readl(HPET_COUNTER) <  trigger)
> +             int trigger;
> +             do
> +                     trigger = hpet_readl(HPET_T0_CMP);
> +             while (hpet_readl(HPET_COUNTER) >= trigger);
> +

Is this signedness-safe and wraparound-safe?  It might be better to make
`trigger' unsigned and do

        while (hpet_readl(HPET_COUNTER) - trigger >= 0)

> +             while (hpet_readl(HPET_COUNTER) <  trigger)
>                       /* do nothing */ ;

ditto.
-
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