1 files changed, 22 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index 5c28b37dea11..fb039cd345d8 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -939,10 +939,25 @@ static void powernow_k8_cpu_exit_acpi(struct powernow_k8_data *data)
         free_cpumask_var(data->acpi_data.shared_cpu_map);
 }
 
+static int get_transition_latency(struct powernow_k8_data *data)
+{
+        int max_latency = 0;
+        int i;
+        for (i = 0; i < data->acpi_data.state_count; i++) {
+                int cur_latency = data->acpi_data.states[i].transition_latency
+                        + data->acpi_data.states[i].bus_master_latency;
+                if (cur_latency > max_latency)
+                        max_latency = cur_latency;
+        }
+        /* value in usecs, needs to be in nanoseconds */
+        return 1000 * max_latency;
+}
+
 #else
 static int powernow_k8_cpu_init_acpi(struct powernow_k8_data *data) { return -ENODEV; }
 static void powernow_k8_cpu_exit_acpi(struct powernow_k8_data *data) { return; }
 static void powernow_k8_acpi_pst_values(struct powernow_k8_data *data, unsigned int index) { return; }
+static int get_transition_latency(struct powernow_k8_data *data) { return 0; }
 #endif /* CONFIG_X86_POWERNOW_K8_ACPI */
 
 /* Take a frequency, and issue the fid/vid transition command */
@@ -1173,7 +1188,13 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
                 if (rc) {
                         goto err_out;
                 }
-        }
+                /* Take a crude guess here.
+                 * That guess was in microseconds, so multiply with 1000 */
+                pol->cpuinfo.transition_latency = (
+                         ((data->rvo + 8) * data->vstable * VST_UNITS_20US) +
+                         ((1 << data->irt) * 30)) * 1000;
+        } else /* ACPI _PSS objects available */
+                pol->cpuinfo.transition_latency = get_transition_latency(data);
 
         /* only run on specific CPU from here on */
         oldmask = current->cpus_allowed;
@@ -1204,11 +1225,6 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
                 cpumask_copy(pol->cpus, &per_cpu(cpu_core_map, pol->cpu));
         data->available_cores = pol->cpus;
 
-        /* Take a crude guess here.
-         * That guess was in microseconds, so multiply with 1000 */
-        pol->cpuinfo.transition_latency = (((data->rvo + 8) * data->vstable * VST_UNITS_20US)
-            + (3 * (1 << data->irt) * 10)) * 1000;
-
         if (cpu_family == CPU_HW_PSTATE)
                 pol->cur = find_khz_freq_from_pstate(data->powernow_table, data->currpstate);
         else