[RFC][PATCH] ACPI: Ignore invalid _PSS entries, but use valid ones

[Marco Aurelio da Costa <costa@xxxxxxxxx>]

From: Marco Aurelio da Costa <costa@xxxxxxxxx>
Signed-off-by: Marco Aurelio da Costa <costa@xxxxxxxxx>

The EliteBook 8560W has non-initialized entries in its _PSS ACPI
table. Instead of bailing out when the first non-initialized entry is
found, ignore it and use only  the valid entries. Only bail out if there
is no valid entry at all.

---
--- linux-3.3.3/drivers/acpi/processor_perflib.c.orig   2012-04-24
22:18:23.288041268 +0200
+++ linux-3.3.3/drivers/acpi/processor_perflib.c        2012-04-24
22:19:25.912042603 +0200
@@ -311,6 +311,7 @@ static int acpi_processor_get_performanc
       struct acpi_buffer state = { 0, NULL };
       union acpi_object *pss = NULL;
       int i;
+       int last_invalid = -1;


       status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
@@ -374,12 +375,30 @@ static int acpi_processor_get_performanc
                       printk(KERN_ERR FW_BUG PREFIX
                              "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
                              px->core_frequency);
-                       result = -EFAULT;
-                       kfree(pr->performance->states);
-                       goto end;
+                       if (-1 == last_invalid)
+                               last_invalid = i;
+               } else {
+                       if (last_invalid != -1) {
+                               /*
+                                * Copy this valid entry over last_invalid entry
+                                */
+                               memcpy(&(pr->performance->states[last_invalid]),
+                                      px, sizeof(struct acpi_processor_px));
+                               ++last_invalid;
+                       }
               }
       }

+       if (0 == last_invalid) {
+               printk(KERN_ERR FW_BUG PREFIX
+                      "No valid BIOS _PSS frequency found\n");
+               result = -EFAULT;
+               kfree(pr->performance->states);
+       }
+
+       if (last_invalid > 0)
+               pr->performance->state_count = last_invalid;
+
      end:
       kfree(buffer.pointer);
--
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