[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>

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 83fd1b6..40c9f9c 100644 (file)
--- 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