1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index a093dc163a42..836bfe069042 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -324,6 +324,34 @@ static int acpi_processor_get_performance_control(struct acpi_processor *pr)
         return result;
 }
 
+#ifdef CONFIG_X86
+/*
+ * Some AMDs have 50MHz frequency multiples, but only provide 100MHz rounding
+ * in their ACPI data. Calculate the real values and fix up the _PSS data.
+ */
+static void amd_fixup_frequency(struct acpi_processor_px *px, int i)
+{
+        u32 hi, lo, fid, did;
+        int index = px->control & 0x00000007;
+
+        if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+                return;
+
+        if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
+            || boot_cpu_data.x86 == 0x11) {
+                rdmsr(MSR_AMD_PSTATE_DEF_BASE + index, lo, hi);
+                fid = lo & 0x3f;
+                did = (lo >> 6) & 7;
+                if (boot_cpu_data.x86 == 0x10)
+                        px->core_frequency = (100 * (fid + 0x10)) >> did;
+                else
+                        px->core_frequency = (100 * (fid + 8)) >> did;
+        }
+}
+#else
+static void amd_fixup_frequency(struct acpi_processor_px *px, int i) {};
+#endif
+
 static int acpi_processor_get_performance_states(struct acpi_processor *pr)
 {
         int result = 0;
@@ -379,6 +407,8 @@ static int acpi_processor_get_performance_states(struct acpi_processor *pr)
                         goto end;
                 }
 
+                amd_fixup_frequency(px, i);
+
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                   "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
                                   i,