linux-kernel - Re: [PATCH 1/2] v4 x86/mrst: add cpu type detection

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Message-ID: <alpine.LFD.2.00.1005182250460.3368@localhost.localdomain>
Date:	Tue, 18 May 2010 22:54:47 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Jacob Pan <jacob.jun.pan@...ux.intel.com>
cc:	LKML <linux-kernel@...r.kernel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	Alek Du <alek.du@...el.com>, Alan Cox <alan@...ux.intel.com>,
	Feng Tang <feng.tang@...el.com>
Subject: Re: [PATCH 1/2] v4 x86/mrst: add cpu type detection

On Tue, 18 May 2010, Jacob Pan wrote:
>  
> +int mrst_identify_cpu(void)
> +{
> +	u32 mrst_cpu_chip;
> +
> +	if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 0x27)
> +		mrst_cpu_chip = MRST_CPU_CHIP_PENWELL;
> +	else if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 0x26)
> +		mrst_cpu_chip = MRST_CPU_CHIP_LINCROFT;
> +	else {
> +		pr_err("Unknown Moorestown CPU (%d:%d), default to Lincroft\n",
> +			boot_cpu_data.x86, boot_cpu_data.x86_model);
> +		mrst_cpu_chip = MRST_CPU_CHIP_LINCROFT;
> +	}
> +	pr_debug("Moorestown CPU %s identified\n",
> +		(mrst_cpu_chip == MRST_CPU_CHIP_LINCROFT) ?
> +		"Lincroft" : "Penwell");

  Do you really want a printk for each call ?

  Aside of that wouldn't it make more sense to do the chip
  identification only once from mrst_init() and cache the result and
  change mrst_identify_cpu()

int mrst_indetify_cpu(void)
{
	return mrst_cpu_chip;
}
EXPORT_SYMBOL_GPL(mrst_identify_cpu);

I think one of your earlier versions did that, but was not consistent
in it's behaviour.

Thanks,

	tglx
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