ACPI: extend "acpi_osi=" boot option

The boot option "acpi_osi=" has always disabled Linux _OSI support,
thus disabling all OS Interface strings which are advertised
by Linux to the BIOS.

Now...
acpi_osi="string" adds the interface string, and
acpi_osi="!string" invalidates the pre-defined interface string

eg. acpi_osi="!Windows 2006"
would disable Linux's claim of Vista compatibility.

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

1 files changed, 16 insertions, 9 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index b998340e23d..f4760cfa61e 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -73,6 +73,9 @@ static void *acpi_irq_context;
 static struct workqueue_struct *kacpid_wq;
 static struct workqueue_struct *kacpi_notify_wq;
 
+#define OSI_STRING_LENGTH_MAX 64        /* arbitrary */
+static char osi_additional_string[OSI_STRING_LENGTH_MAX];
+
 static void __init acpi_request_region (struct acpi_generic_address *addr,
         unsigned int length, char *desc)
 {
@@ -961,19 +964,23 @@ static int __init acpi_os_name_setup(char *str)
 __setup("acpi_os_name=", acpi_os_name_setup);
 
 /*
- * _OSI control
+ * Modify the list of "OS Interfaces" reported to BIOS via _OSI
+ *
  * empty string disables _OSI
- * TBD additional string adds to _OSI
+ * string starting with '!' disables that string
+ * otherwise string is added to list, augmenting built-in strings
  */
 static int __init acpi_osi_setup(char *str)
 {
         if (str == NULL || *str == '\0') {
                 printk(KERN_INFO PREFIX "_OSI method disabled\n");
                 acpi_gbl_create_osi_method = FALSE;
-        } else {
-                /* TBD */
-                printk(KERN_ERR PREFIX "_OSI additional string ignored -- %s\n",
-                       str);
+        } else if (*str == '!') {
+                if (acpi_osi_invalidate(++str) == AE_OK)
+                        printk(KERN_INFO PREFIX "Deleted _OSI(%s)\n", str);
+        } else if (*osi_additional_string == '\0') {
+                strncpy(osi_additional_string, str, OSI_STRING_LENGTH_MAX);
+                printk(KERN_INFO PREFIX "Added _OSI(%s)\n", str);
         }
 
         return 1;
@@ -1143,11 +1150,11 @@ acpi_status acpi_os_release_object(acpi_cache_t * cache, void *object)
 acpi_status
 acpi_os_validate_interface (char *interface)
 {
-
-    return AE_SUPPORT;
+        if (!strncmp(osi_additional_string, interface, OSI_STRING_LENGTH_MAX))
+                return AE_OK;
+        return AE_SUPPORT;
 }
 
-
 /******************************************************************************
  *
  * FUNCTION:    acpi_os_validate_address