[PATCH] Fix warning in powernow-k8.c

[PATCH] Fix warning in powernow-k8.c

[Brian Gerst]

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Fix this warning:
powernow-k8.c: In function ‘query_current_values_with_pending_wait’:
powernow-k8.c:110: warning: ‘hi’ may be used uninitialized in this function

Signed-off-by: Brian Gerst <bgerst@didntduck.org>

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diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
@@ -110,14 +110,13 @@ static int query_current_values_with_pen
 	u32 lo, hi;
 	u32 i = 0;
 
-	lo = MSR_S_LO_CHANGE_PENDING;
-	while (lo & MSR_S_LO_CHANGE_PENDING) {
+	do {
 		if (i++ > 0x1000000) {
 			printk(KERN_ERR PFX "detected change pending stuck\n");
 			return 1;
 		}
 		rdmsr(MSR_FIDVID_STATUS, lo, hi);
-	}
+	} while (lo & MSR_S_LO_CHANGE_PENDING);
 
 	data->currvid = hi & MSR_S_HI_CURRENT_VID;
 	data->currfid = lo & MSR_S_LO_CURRENT_FID;

Re: [PATCH] Fix warning in powernow-k8.c

[Pavel Machek]

Hi!

> Fix this warning:
> powernow-k8.c: In function ?query_current_values_with_pending_wait?:
> powernow-k8.c:110: warning: ?hi? may be used uninitialized in this
> function

Are you sure?

Original code is clearly buggy; I do not think you need that ugly do
{} while loop.

								Pavel
> 
> Signed-off-by: Brian Gerst <bgerst@didntduck.org>

> diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
> --- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
> +++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
> @@ -110,14 +110,13 @@ static int query_current_values_with_pen
>  	u32 lo, hi;
>  	u32 i = 0;
>  
> -	lo = MSR_S_LO_CHANGE_PENDING;
> -	while (lo & MSR_S_LO_CHANGE_PENDING) {
> +	do {
>  		if (i++ > 0x1000000) {
>  			printk(KERN_ERR PFX "detected change pending stuck\n");
>  			return 1;
>  		}
>  		rdmsr(MSR_FIDVID_STATUS, lo, hi);
> -	}
> +	} while (lo & MSR_S_LO_CHANGE_PENDING);
>  
>  	data->currvid = hi & MSR_S_HI_CURRENT_VID;
>  	data->currfid = lo & MSR_S_LO_CURRENT_FID;


-- 

Re: [PATCH] Fix warning in powernow-k8.c

[Brian Gerst]

Pavel Machek wrote:
> Hi!
> 
> 
>>Fix this warning:
>>powernow-k8.c: In function ?query_current_values_with_pending_wait?:
>>powernow-k8.c:110: warning: ?hi? may be used uninitialized in this
>>function
> 
> 
> Are you sure?
> 
> Original code is clearly buggy; I do not think you need that ugly do
> {} while loop.

I'm not sure why you think the loop is ugly.  It makes it more obvious 
(to us humans and the compiler) that the loop is executed at least one time.

> 
> 								Pavel
> 
>>Signed-off-by: Brian Gerst <bgerst@didntduck.org>
> 
> 
>>diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
>>--- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
>>+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
>>@@ -110,14 +110,13 @@ static int query_current_values_with_pen
>> 	u32 lo, hi;
>> 	u32 i = 0;
>> 
>>-	lo = MSR_S_LO_CHANGE_PENDING;
>>-	while (lo & MSR_S_LO_CHANGE_PENDING) {
>>+	do {
>> 		if (i++ > 0x1000000) {
>> 			printk(KERN_ERR PFX "detected change pending stuck\n");
>> 			return 1;
>> 		}
>> 		rdmsr(MSR_FIDVID_STATUS, lo, hi);
>>-	}
>>+	} while (lo & MSR_S_LO_CHANGE_PENDING);
>> 
>> 	data->currvid = hi & MSR_S_HI_CURRENT_VID;
>> 	data->currfid = lo & MSR_S_LO_CURRENT_FID;
> 
> 
> 

Re: [PATCH] Fix warning in powernow-k8.c

[Pavel Machek]

On Pá 03-06-05 14:31:48, Brian Gerst wrote:
> Pavel Machek wrote:
> >Hi!
> >
> >
> >>Fix this warning:
> >>powernow-k8.c: In function ?query_current_values_with_pending_wait?:
> >>powernow-k8.c:110: warning: ?hi? may be used uninitialized in this
> >>function
> >
> >
> >Are you sure?
> >
> >Original code is clearly buggy; I do not think you need that ugly do
> >{} while loop.
> 
> I'm not sure why you think the loop is ugly.  It makes it more obvious 
> (to us humans and the compiler) that the loop is executed at least
> one time.

Oops, sorry, I misread the patch.
								Pavel