Re: [PATCH 1/3] intel_pstate: skip the driver if Sun server has ACPI _PPC method

From: Linda Knippers
Date: Wed Nov 19 2014 - 15:22:20 EST


On 11/18/2014 3:37 AM, Ethan Zhao wrote:
> Oracle Sun X86 servers have dynamic power capping capability that works via
> ACPI _PPC method etc, so skip loading this driver if Sun server has ACPI _PPC
> enabled.
>
> Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> ---
> drivers/cpufreq/intel_pstate.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 27bb6d3..5498eb0 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -943,6 +943,21 @@ static bool intel_pstate_no_acpi_pss(void)
> return true;
> }
>
> +static bool intel_pstate_has_acpi_ppc(void)
> +{
> + int i;
> +
> + for_each_possible_cpu(i) {
> + struct acpi_processor *pr = per_cpu(processors, i);
> +
> + if (!pr)
> + continue;
> + if (acpi_has_method(pr->handle, "_PPC"))
> + return true;
> + }
> + return false;
> +}
> +
> struct hw_vendor_info {
> u16 valid;
> char oem_id[ACPI_OEM_ID_SIZE];
> @@ -952,6 +967,7 @@ struct hw_vendor_info {
> /* Hardware vendor-specific info that has its own power management modes */
> static struct hw_vendor_info vendor_info[] = {
> {1, "HP ", "ProLiant"},
> + {1, "ORACLE", ""},
> {0, "", ""},
> };
>
> @@ -969,12 +985,16 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
> !strncmp(hdr.oem_table_id, v_info->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
> intel_pstate_no_acpi_pss())
> return true;
> + if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE) &&
> + intel_pstate_has_acpi_ppc())

We need try this on a few platforms to make sure this patch doesn't break the
HP platforms that may or may not need this driver, depending on the BIOS settings.

I don't suppose you tested on a ProLiant too?

-- ljk

> + return true;
> }
>
> return false;
> }
> #else /* CONFIG_ACPI not enabled */
> static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { return false; }
> +static inline bool intel_pstate_has_acpi_ppc(void) { return false; }
> #endif /* CONFIG_ACPI */
>
> static int __init intel_pstate_init(void)
>

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