linux-kernel - Re: [PATCH] x86, intel, power: Modify the MSR_IA32_ENERGY_PERF

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Date:	Thu, 25 Oct 2012 11:49:14 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Ivan Hu <ivan.hu@...onical.com>
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, alex.shi@...el.com, borislav.petkov@....com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86, intel, power: Modify the MSR_IA32_ENERGY_PERF_BIAS
 message from warning to info

On Thu, Oct 25, 2012 at 05:28:00PM +0800, Ivan Hu wrote:
> Intel IA32 program guild doesn't mention that this MSR should be set by
> BIOS, instead, it mentions "Software can use whatever criteria it sees
> fit to program the MSR with the appropriate value.". Discuss with IBV,
> they'd like to keep this MSR as default, and let OS to change value if desired.
> This message should be more proper set as an info than a warning.

What is the difference? It'll appear in default dmesg loglevel settings
anyway.

> Signed-off-by: Ivan Hu <ivan.hu@...onical.com>
> ---
>  arch/x86/kernel/cpu/intel.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index 198e019..2bdc6bf 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -466,7 +466,7 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
>  
>  		rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
>  		if ((epb & 0xF) == ENERGY_PERF_BIAS_PERFORMANCE) {
> -			printk_once(KERN_WARNING "ENERGY_PERF_BIAS:"
> +			printk_once(KERN_INFO "ENERGY_PERF_BIAS:"

While you're at it, you can do pr_info_once to shorten this line a bit.

>  				" Set to 'normal', was 'performance'\n"
>  				"ENERGY_PERF_BIAS: View and update with"
>  				" x86_energy_perf_policy(8)\n");
> -- 
> 1.7.10.4

-- 
Regards/Gruss,
    Boris.
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