Re: [PATCH]: cpufreq: pcc-cpufreq: don't load driver if get_freq fails during init.

[Thomas Renninger <trenn@suse.de>]

Good catch.

On Wednesday, March 09, 2011 03:02:49 PM Naga Chumbalkar wrote:
> 
> Return 0 on failure. This will cause the initialization of the driver
> to fail and prevent the driver from loading if the BIOS cannot handle
> the PCC interface command to "get frequency". Otherwise, the driver
> will load and display a very high value like "4294967274" (which is
> actually -EINVAL) for frequency:
> 
> # cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
> 4294967274
> 
> Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>

While this is not a regression, it's an easy fix.
It should make sense to add:
CC: stable@kernel.org
?

   Thomas
> ---
> 
> diff --git a/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c 
b/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
> index 4f6f679..4a5a42b 100644
> --- a/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
> +++ b/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
> @@ -195,7 +195,7 @@ static unsigned int pcc_get_freq(unsigned int cpu)
>  cmd_incomplete:
>  	iowrite16(0, &pcch_hdr->status);
>  	spin_unlock(&pcc_lock);
> -	return -EINVAL;
> +	return 0;
>  }
>  
>  static int pcc_cpufreq_target(struct cpufreq_policy *policy,
> --
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