From acd316248205d553594296f1895ba5196b89ffcc Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 4 Sep 2012 08:28:03 +0000 Subject: [PATCH] acpi-cpufreq: Add quirk to disable _PSD usage on all AMD CPUs To workaround some Windows specific behavior, the ACPI _PSD table on AMD desktop boards advertises all cores as dependent, meaning that they all can only use the same P-state. acpi-cpufreq strictly obeys this description, instantiating one CPU only and symlinking the others. But the hardware can have distinct frequencies for each core and powernow-k8 did it that way. So, in order to use the hardware to its full potential and keep the original powernow-k8 behavior, lets override the _PSD table setting on AMD hardware. We use the siblings table, as it matches the current hardware behavior. Signed-off-by: Andre Przywara Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/acpi-cpufreq.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index 067a61f06bb5..70e717305c29 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -51,6 +51,8 @@ MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski"); MODULE_DESCRIPTION("ACPI Processor P-States Driver"); MODULE_LICENSE("GPL"); +#define PFX "acpi-cpufreq: " + enum { UNDEFINED_CAPABLE = 0, SYSTEM_INTEL_MSR_CAPABLE, @@ -586,6 +588,14 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; cpumask_copy(policy->cpus, cpu_core_mask(cpu)); } + + if (check_amd_hwpstate_cpu(cpu) && !acpi_pstate_strict) { + cpumask_clear(policy->cpus); + cpumask_set_cpu(cpu, policy->cpus); + cpumask_copy(policy->related_cpus, cpu_sibling_mask(cpu)); + policy->shared_type = CPUFREQ_SHARED_TYPE_HW; + pr_info_once(PFX "overriding BIOS provided _PSD data\n"); + } #endif /* capability check */