1 files changed, 41 insertions, 18 deletions

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 3f55d1f90c11..0b8204e7082a 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -47,6 +47,9 @@ ACPI_MODULE_NAME("processor_throttling");
 static int acpi_processor_get_throttling(struct acpi_processor *pr);
 int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
 
+/*
+ * _TPC - Throttling Present Capabilities
+ */
 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
 {
         acpi_status status = 0;
@@ -55,8 +58,10 @@ static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
         if (!pr)
                 return -EINVAL;
         status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
-        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
-                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
+        if (ACPI_FAILURE(status)) {
+                if (status != AE_NOT_FOUND) {
+                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
+                }
                 return -ENODEV;
         }
         pr->throttling_platform_limit = (int)tpc;
@@ -68,9 +73,9 @@ int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
         return acpi_processor_get_platform_limit(pr);
 }
 
-/* --------------------------------------------------------------------------
-                             _PTC, _TSS, _TSD support 
-   -------------------------------------------------------------------------- */
+/*
+ * _PTC - Processor Throttling Control (and status) register location
+ */
 static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
 {
         int result = 0;
@@ -81,7 +86,9 @@ static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
 
         status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
         if (ACPI_FAILURE(status)) {
-                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
+                if (status != AE_NOT_FOUND) {
+                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
+                }
                 return -ENODEV;
         }
 
@@ -132,6 +139,10 @@ static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
 
         return result;
 }
+
+/*
+ * _TSS - Throttling Supported States
+ */
 static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 {
         int result = 0;
@@ -144,7 +155,9 @@ static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 
         status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
         if (ACPI_FAILURE(status)) {
-                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
+                if (status != AE_NOT_FOUND) {
+                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
+                }
                 return -ENODEV;
         }
 
@@ -201,6 +214,10 @@ static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
 
         return result;
 }
+
+/*
+ * _TSD - T-State Dependencies
+ */
 static int acpi_processor_get_tsd(struct acpi_processor *pr)
 {
         int result = 0;
@@ -213,6 +230,9 @@ static int acpi_processor_get_tsd(struct acpi_processor *pr)
 
         status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
         if (ACPI_FAILURE(status)) {
+                if (status != AE_NOT_FOUND) {
+                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
+                }
                 return -ENODEV;
         }
 
@@ -525,9 +545,6 @@ int acpi_processor_get_throttling_info(struct acpi_processor *pr)
         int result = 0;
         int step = 0;
         int i = 0;
-        int no_ptc = 0;
-        int no_tss = 0;
-        int no_tsd = 0;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                           "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
@@ -538,12 +555,14 @@ int acpi_processor_get_throttling_info(struct acpi_processor *pr)
         if (!pr)
                 return -EINVAL;
 
-        /* TBD: Support ACPI 2.0 objects */
-        no_ptc = acpi_processor_get_throttling_control(pr);
-        no_tss = acpi_processor_get_throttling_states(pr);
-        no_tsd = acpi_processor_get_tsd(pr);
-
-        if (no_ptc || no_tss) {
+        /*
+         * Evaluate _PTC, _TSS and _TPC
+         * They must all be present or none of them can be used.
+         */
+        if (acpi_processor_get_throttling_control(pr) ||
+                acpi_processor_get_throttling_states(pr) ||
+                acpi_processor_get_platform_limit(pr))
+        {
                 pr->throttling.acpi_processor_get_throttling =
                     &acpi_processor_get_throttling_fadt;
                 pr->throttling.acpi_processor_set_throttling =
@@ -555,6 +574,8 @@ int acpi_processor_get_throttling_info(struct acpi_processor *pr)
                     &acpi_processor_set_throttling_ptc;
         }
 
+        acpi_processor_get_tsd(pr);
+
         if (!pr->throttling.address) {
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
                 return 0;
@@ -658,18 +679,20 @@ static int acpi_processor_throttling_seq_show(struct seq_file *seq,
                    pr->throttling.state_count - 1);
 
         seq_puts(seq, "states:\n");
-        if (acpi_processor_get_throttling == acpi_processor_get_throttling_fadt)
+        if (pr->throttling.acpi_processor_get_throttling ==
+                        acpi_processor_get_throttling_fadt) {
                 for (i = 0; i < pr->throttling.state_count; i++)
                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
                                    (i == pr->throttling.state ? '*' : ' '), i,
                                    (pr->throttling.states[i].performance ? pr->
                                     throttling.states[i].performance / 10 : 0));
-        else
+        } else {
                 for (i = 0; i < pr->throttling.state_count; i++)
                         seq_printf(seq, "   %cT%d:                  %02d%%\n",
                                    (i == pr->throttling.state ? '*' : ' '), i,
                                    (int)pr->throttling.states_tss[i].
                                    freqpercentage);
+        }
 
       end:
         return 0;