Re: [Xen-devel] [PATCH 2/2] cpufreq: fix turbo mode state reporting

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 19.06.13 at 22:14, Jacob Shin <jacob.shin@xxxxxxx> wrote:
> Currently we report back 0 or 1, which is broken since xenpm expects
> CPUFREQ_TURBO_DISABLED, CPUFREQ_TURBO_UNSUPPORTED, or
> CPUFREQ_TURBO_ENABLED. Report back actual policy->turbo value instead.

I think that it's xenpm that's wrong here - the three constants above
aren't exposed in public headers, and hence aren't part of the ABI.
Furthermore the structure member name that the result of this
function gets stored into is "turbo_enabled", which also suggests a
boolean value to me. I.e. if we want to change the value set that
the hypervisor may return here, the field should also get renamed,
and the value set exposed.

> --- a/xen/drivers/cpufreq/utility.c
> +++ b/xen/drivers/cpufreq/utility.c
> @@ -428,7 +428,10 @@ int cpufreq_get_turbo_status(int cpuid)
>      struct cpufreq_policy *policy;
>  
>      policy = per_cpu(cpufreq_cpu_policy, cpuid);
> -    return policy && policy->turbo;
> +    if (!policy)
> +        return CPUFREQ_TURBO_UNSUPPORTED;
> +
> +    return policy->turbo;

Nevertheless this would need adjustment even for the boolean
value case:

-    return policy && policy->turbo;
+    return policy && policy->turbo == CPUFREQ_TURBO_ENABLED;

Jan



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