On Mon, Aug 29, 2011 at 02:28:27PM -0400, Matthew Garrett wrote:
> The ACPI thermal management code supports slowing down a CPU when it's
> overheating. Right now that's done by choosing to run it at 100%, 75%, 50%
> or 25% of full speed. However, most CPUs do not allow an arbitrary
> frequency to be set and so will run at the first frequency below that value.
> This doesn't match the intent of the specification, which is to drop the
> frequency state by state until the temperature stabalises. Fix this up
> so it uses actual frequencies rather than percentages.
>
> Reported by: Gene Snider <snider6982@xxxxxxxxxxx>
> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
> ---
> drivers/acpi/processor_thermal.c | 45 +++++++++++++++++++++----------------
> 1 files changed, 25 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
> index 870550d..1c4eb60 100644
> --- a/drivers/acpi/processor_thermal.c
> +++ b/drivers/acpi/processor_thermal.c
> @@ -52,10 +52,8 @@ ACPI_MODULE_NAME("processor_thermal");
> * _any_ cpufreq driver and not only the acpi-cpufreq driver.
> */
>
> -#define CPUFREQ_THERMAL_MIN_STEP 0
> -#define CPUFREQ_THERMAL_MAX_STEP 3
>
> -static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
> +static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_limit_state);
> static unsigned int acpi_thermal_cpufreq_is_init = 0;
>
> static int cpu_has_cpufreq(unsigned int cpu)
> @@ -70,19 +68,19 @@ static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
> unsigned long event, void *data)
> {
> struct cpufreq_policy *policy = data;
> - unsigned long max_freq = 0;
> + int state = per_cpu(cpufreq_thermal_limit_state, policy->cpu);
> + struct cpufreq_frequency_table *table;
>
> if (event != CPUFREQ_ADJUST)
> - goto out;
> + return 0;
> +
> + table = cpufreq_frequency_get_table(policy->cpu);
If CONFIG_CPU_FREQ_TABLE=m and CONFIG_ACPI_PROCESSOR=y, you'll get a
link error for an undefined symbol on this. This requires
ACPI_PROCESSOR to select CPU_FREQ_TABLE.
josh
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