Re: [PATCH] cpufreq/intel_pstate: Add kernel command line optiondisable intel_pstate.

From: Yinghai Lu
Date: Thu Feb 14 2013 - 17:56:29 EST


On Thu, Feb 14, 2013 at 10:38 AM, <dirk.brandewie@xxxxxxxxx> wrote:
> From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>
>
> When intel_pstate is configured into the kernel it will become the
> perferred scaling driver for processors that is supports. Allow the
> user to override this by adding:
> intel_pstate=disable
> on the kernel command line.
>
> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
> ---
> Documentation/kernel-parameters.txt | 5 +++++
> drivers/cpufreq/intel_pstate.c | 16 ++++++++++++++++
> 2 files changed, 21 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 6c72381..41c5d9e 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1131,6 +1131,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> 0 disables intel_idle and fall back on acpi_idle.
> 1 to 6 specify maximum depth of C-state.
>
> + intel_pstate= [X86]
> + disable
> + Do not enable intel_pstate as the default
> + scaling driver for the supported processors
> +
> intremap= [X86-64, Intel-IOMMU]
> on enable Interrupt Remapping (default)
> off disable Interrupt Remapping
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index e879963..9cbb733 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -773,11 +773,16 @@ static void intel_pstate_exit(void)
> }
> module_exit(intel_pstate_exit);
>
> +static int no_load;

Looks like you can use __initdata with it.

Thanks

Yinghai


> +
> static int __init intel_pstate_init(void)
> {
> int rc = 0;
> const struct x86_cpu_id *id;
>
> + if (no_load)
> + return -ENODEV;
> +
> id = x86_match_cpu(intel_pstate_cpu_ids);
> if (!id)
> return -ENODEV;
> @@ -802,6 +807,17 @@ out:
> }
> device_initcall(intel_pstate_init);
>
> +static int __init intel_pstate_setup(char *str)
> +{
> + if (!str)
> + return -EINVAL;
> +
> + if (!strcmp(str, "disable"))
> + no_load = 1;
> + return 0;
> +}
> +early_param("intel_pstate", intel_pstate_setup);
> +
> MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>");
> MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
> MODULE_LICENSE("GPL");
> --
> 1.7.7.6
>
> --
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