linux-kernel - Re: [PATCH] [1/3] Only do century BCD conversion when we know the RTC is BCD

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Date:	Sat, 9 Feb 2008 11:28:01 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andi Kleen <ak@...e.de>
cc:	mingo@...e.hu, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [1/3] Only do century BCD conversion when we know the
 RTC is BCD

On Fri, 8 Feb 2008, Andi Kleen wrote:

> 
> Minor logic fix. The century change was previously always BCD,
> even when the CMOS data would report itself not being BCD.

Where was it previously always BCD ?

The code flow is taken 1:1 from the original x8664 code. Just the
BCD_TO_BIN code has been made conditional for i386, which is not
chanining the logic at all, because RTC_ALWAYS_BCD is always true on
x8664.

While your change does not do any harm due to BCD_TO_BIN(0) = 0, it
is just not fixing anything.

Thanks,
	tglx
 
> Signed-off-by: Andi Kleen <ak@...e.de>
> 
> ---
>  arch/x86/kernel/rtc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux/arch/x86/kernel/rtc.c
> ===================================================================
> --- linux.orig/arch/x86/kernel/rtc.c
> +++ linux/arch/x86/kernel/rtc.c
> @@ -130,10 +130,10 @@ unsigned long mach_get_cmos_time(void)
>  		BCD_TO_BIN(day);
>  		BCD_TO_BIN(mon);
>  		BCD_TO_BIN(year);
> +		BCD_TO_BIN(century);
>  	}
>  
>  	if (century) {
> -		BCD_TO_BIN(century);
>  		year += century * 100;
>  		printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
>  	} else {
> 
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