ACPICA: add debug dump of BIOS _OSI strings

on boot, print out the OSI strings the BIOS uses to query the OS.

To see this output...

build with CONFIG_ACPI_DEBUG

boot with
"acpi.debug_level=4" (ACPI_LV_INFO) (enabled by default)
and
"acpi.debug_level=1" (ACPI_UTILITIES) (default is 0)

example output:

ACPI: BIOS _OSI(Windows 2001) supported
ACPI: BIOS _OSI(Windows 2001 SP1) supported
ACPI: BIOS _OSI(Windows 2001 SP2) supported
ACPI: BIOS _OSI(Windows 2006) supported
ACPI: BIOS _OSI(Linux) not-supported
ACPI: BIOS _OSI(FreeBSD) not-supported

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 9 insertions, 12 deletions

diff --git a/drivers/acpi/acpica/uteval.c b/drivers/acpi/acpica/uteval.c
index da9450bc60f7..9c9897dbe907 100644
--- a/drivers/acpi/acpica/uteval.c
+++ b/drivers/acpi/acpica/uteval.c
@@ -116,9 +116,9 @@ acpi_status acpi_ut_osi_implementation(struct acpi_walk_state *walk_state)
                 return_ACPI_STATUS(AE_NO_MEMORY);
         }
 
-        /* Default return value is SUPPORTED */
+        /* Default return value is 0, NOT-SUPPORTED */
 
-        return_desc->integer.value = ACPI_UINT32_MAX;
+        return_desc->integer.value = 0;
         walk_state->return_desc = return_desc;
 
         /* Compare input string to static table of supported interfaces */
@@ -127,10 +127,8 @@ acpi_status acpi_ut_osi_implementation(struct acpi_walk_state *walk_state)
                 if (!ACPI_STRCMP
                     (string_desc->string.pointer,
                      acpi_interfaces_supported[i])) {
-
-                        /* The interface is supported */
-
-                        return_ACPI_STATUS(AE_OK);
+                        return_desc->integer.value = ACPI_UINT32_MAX;
+                        goto done;
                 }
         }
 
@@ -141,15 +139,14 @@ acpi_status acpi_ut_osi_implementation(struct acpi_walk_state *walk_state)
          */
         status = acpi_os_validate_interface(string_desc->string.pointer);
         if (ACPI_SUCCESS(status)) {
-
-                /* The interface is supported */
-
-                return_ACPI_STATUS(AE_OK);
+                return_desc->integer.value = ACPI_UINT32_MAX;
         }
 
-        /* The interface is not supported */
+done:
+        ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO, "ACPI: BIOS _OSI(%s) %ssupported\n",
+                string_desc->string.pointer,
+                return_desc->integer.value == 0 ? "not-" : ""));
 
-        return_desc->integer.value = 0;
         return_ACPI_STATUS(AE_OK);
 }