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authorAndre Przywara <andre.przywara@amd.com>2012-09-04 08:28:03 +0000
committerRafael J. Wysocki <rjw@sisk.pl>2012-09-09 22:04:34 +0200
commitacd316248205d553594296f1895ba5196b89ffcc (patch)
treec056ba67e8666867ee5f4c9acc7d665f1c0dbd61 /drivers
parent3dc9a633f8a65b39c5897874138027328bfb0a94 (diff)
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 <andre.przywara@amd.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/acpi-cpufreq.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 067a61f06bb..70e717305c2 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 */