linux-kernel - Re: [PATCH 4/10 -tip] x86: check_powernow() for K7 user of Advanced Power Management features

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Message-Id: <1242155279.2492.75.camel@ht.satnam>
Date:	Wed, 13 May 2009 00:37:59 +0530
From:	Jaswinder Singh Rajput <jaswinder@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	"H. Peter Anvin" <hpa@...nel.org>,
	Robert Richter <robert.richter@....com>,
	Dave Jones <davej@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	x86 maintainers <x86@...nel.org>
Subject: Re: [PATCH 4/10 -tip] x86: check_powernow() for K7 user of
 Advanced Power Management features

On Tue, 2009-05-12 at 21:10 +0530, Jaswinder Singh Rajput wrote:
> use X86_FEATURE_FID and X86_FEATURE_VID to determine K7 PowerNOW.
> 
> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@...il.com>
> ---
>  arch/x86/kernel/cpu/cpufreq/powernow-k7.c |   16 ++++++----------
>  1 files changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k7.c b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
> index 3c28ccd..1f35474 100644
> --- a/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
> +++ b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
> @@ -118,7 +118,6 @@ static int check_fsb(unsigned int fsbspeed)
>  static int check_powernow(void)
>  {
>  	struct cpuinfo_x86 *c = &cpu_data(0);
> -	unsigned int maxei, eax, ebx, ecx, edx;
>  
>  	if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 6)) {
>  #ifdef MODULE
> @@ -128,9 +127,8 @@ static int check_powernow(void)
>  		return 0;
>  	}
>  
> -	/* Get maximum capabilities */
> -	maxei = cpuid_eax(0x80000000);
> -	if (maxei < 0x80000007) {	/* Any powernow info ? */
> +	/* Advanced Power Management capabilities */
> +	if (c->x86_capability[9]) {	/* Any powernow info ? */

[PATCH -tip] x86: check_powernow() for K7 user of Advanced Power Management features

use X86_FEATURE_POWER_MGMT, X86_FEATURE_FID and X86_FEATURE_VID
to determine K7 PowerNOW.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@...il.com>
---
 arch/x86/kernel/cpu/cpufreq/powernow-k7.c |   16 ++++++----------
 1 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k7.c b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
index 3c28ccd..965f235 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
@@ -118,7 +118,6 @@ static int check_fsb(unsigned int fsbspeed)
 static int check_powernow(void)
 {
 	struct cpuinfo_x86 *c = &cpu_data(0);
-	unsigned int maxei, eax, ebx, ecx, edx;
 
 	if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 6)) {
 #ifdef MODULE
@@ -128,9 +127,8 @@ static int check_powernow(void)
 		return 0;
 	}
 
-	/* Get maximum capabilities */
-	maxei = cpuid_eax(0x80000000);
-	if (maxei < 0x80000007) {	/* Any powernow info ? */
+	/* Advanced Power Management capabilities */
+	if (!cpu_has(c, X86_FEATURE_POWER_MGMT)) {	/* Any powernow info */
 #ifdef MODULE
 		printk(KERN_INFO PFX "No powernow capabilities detected\n");
 #endif
@@ -143,23 +141,21 @@ static int check_powernow(void)
 		have_a0 = 1;
 	}
 
-	cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
-
 	/* Check we can actually do something before we say anything.*/
-	if (!(edx & (1 << 1 | 1 << 2)))
+	if (!cpu_has(c, X86_FEATURE_FID) && !cpu_has(c, X86_FEATURE_VID))
 		return 0;
 
 	printk(KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");
 
-	if (edx & 1 << 1) {
+	if (cpu_has(c, X86_FEATURE_FID)) {
 		printk("frequency");
 		can_scale_bus = 1;
 	}
 
-	if ((edx & (1 << 1 | 1 << 2)) == 0x6)
+	if (cpu_has(c, X86_FEATURE_FID) && cpu_has(c, X86_FEATURE_VID))
 		printk(" and ");
 
-	if (edx & 1 << 2) {
+	if (cpu_has(c, X86_FEATURE_VID)) {
 		printk("voltage");
 		can_scale_vid = 1;
 	}
-- 
1.6.0.6



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