[ACPI] handle BIOS with implicit C1 in _CST

The ASUS M6Ne specifies C2, implying C1
but not explicitly specifying it.

http://bugzilla.kernel.org/show_bug.cgi?id=4485

Signed-off-by: Janosch Machowinski <jmachowinski@gmx.de>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 31 insertions, 33 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 83fd1b6c10c4..40c9f9ca5965 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -532,18 +532,10 @@ static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
         if (!pr->pblk)
                 return_VALUE(-ENODEV);
 
-        memset(pr->power.states, 0, sizeof(pr->power.states));
-
         /* if info is obtained from pblk/fadt, type equals state */
-        pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 
-        /* the C0 state only exists as a filler in our array,
-         * and all processors need to support C1 */
-        pr->power.states[ACPI_STATE_C0].valid = 1;
-        pr->power.states[ACPI_STATE_C1].valid = 1;
-
 #ifndef CONFIG_HOTPLUG_CPU
         /*
          * Check for P_LVL2_UP flag before entering C2 and above on
@@ -573,12 +565,11 @@ static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
 {
         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
 
+        /* Zero initialize all the C-states info. */
         memset(pr->power.states, 0, sizeof(pr->power.states));
 
-        /* if info is obtained from pblk/fadt, type equals state */
+        /* set the first C-State to C1 */
         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
-        pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
-        pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 
         /* the C0 state only exists as a filler in our array,
          * and all processors need to support C1 */
@@ -592,6 +583,7 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 {
         acpi_status status = 0;
         acpi_integer count;
+        int current_count;
         int i;
         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
         union acpi_object *cst;
@@ -601,10 +593,12 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
         if (nocst)
                 return_VALUE(-ENODEV);
 
-        pr->power.count = 0;
-        for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
-                memset(&(pr->power.states[i]), 0,
-                       sizeof(struct acpi_processor_cx));
+        current_count = 1;
+
+        /* Zero initialize C2 onwards and prepare for fresh CST lookup */
+        for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++)
+                memset(&(pr->power.states[i]), 0, 
+                                sizeof(struct acpi_processor_cx));
 
         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
         if (ACPI_FAILURE(status)) {
@@ -632,16 +626,6 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
                 goto end;
         }
 
-        /* We support up to ACPI_PROCESSOR_MAX_POWER. */
-        if (count > ACPI_PROCESSOR_MAX_POWER) {
-                printk(KERN_WARNING
-                       "Limiting number of power states to max (%d)\n",
-                       ACPI_PROCESSOR_MAX_POWER);
-                printk(KERN_WARNING
-                       "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
-                count = ACPI_PROCESSOR_MAX_POWER;
-        }
-
         /* Tell driver that at least _CST is supported. */
         pr->flags.has_cst = 1;
 
@@ -685,7 +669,7 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
                         continue;
 
-                if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3))
+                if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
                         continue;
 
                 obj = (union acpi_object *)&(element->package.elements[2]);
@@ -700,15 +684,28 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 
                 cx.power = obj->integer.value;
 
-                (pr->power.count)++;
-                memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
+                current_count++;
+                memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
+
+                /*
+                 * We support total ACPI_PROCESSOR_MAX_POWER - 1
+                 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
+                 */
+                if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
+                        printk(KERN_WARNING
+                               "Limiting number of power states to max (%d)\n",
+                               ACPI_PROCESSOR_MAX_POWER);
+                        printk(KERN_WARNING
+                               "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
+                        break;
+                }
         }
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
-                          pr->power.count));
+                          current_count));
 
         /* Validate number of power states discovered */
-        if (pr->power.count < 2)
+        if (current_count < 2)
                 status = -EFAULT;
 
       end:
@@ -859,12 +856,13 @@ static int acpi_processor_get_power_info(struct acpi_processor *pr)
         /* NOTE: the idle thread may not be running while calling
          * this function */
 
+        /* Adding C1 state */
+        acpi_processor_get_power_info_default_c1(pr);
         result = acpi_processor_get_power_info_cst(pr);
         if (result == -ENODEV)
-                result = acpi_processor_get_power_info_fadt(pr);
+                acpi_processor_get_power_info_fadt(pr);
 
-        if ((result) || (acpi_processor_power_verify(pr) < 2))
-                result = acpi_processor_get_power_info_default_c1(pr);
+        pr->power.count = acpi_processor_power_verify(pr);
 
         /*
          * Set Default Policy