acpi: fix _OSI string setup regression

commit b0ed7a91(ACPICA/ACPI: Add new host interfaces for _OSI suppor)
introduced a regression that _OSI string setup fails.

There are 2 paths to setup _OSI string.

DMI:
acpi_dmi_osi_linux -> set_osi_linux -> acpi_osi_setup -> copy _OSI
string to osi_setup_string

Boot command line:
acpi_osi_setup -> copy _OSI string to osi_setup_string

Later, acpi_osi_setup_late will be called to handle osi_setup_string.
If _OSI string is "Linux" or "!Linux", then the call path is,

acpi_osi_setup_late -> acpi_cmdline_osi_linux -> set_osi_linux ->
acpi_osi_setup -> copy _OSI string to osi_setup_string

This actually never installs _OSI string(acpi_install_interface not
called), but just copy the _OSI string to osi_setup_string.

This patch fixes the regression.

Reported-and-tested-by: Lukas Hejtmanek <xhejtman@ics.muni.cz>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 34 insertions, 27 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 966feddf6b1b..6867443c4941 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -152,8 +152,7 @@ static struct osi_linux {
         unsigned int    enable:1;
         unsigned int    dmi:1;
         unsigned int    cmdline:1;
-        unsigned int    known:1;
-} osi_linux = { 0, 0, 0, 0};
+} osi_linux = {0, 0, 0};
 
 static u32 acpi_osi_handler(acpi_string interface, u32 supported)
 {
@@ -1055,13 +1054,22 @@ static int __init acpi_os_name_setup(char *str)
 
 __setup("acpi_os_name=", acpi_os_name_setup);
 
+void __init acpi_osi_setup(char *str)
+{
+        if (!acpi_gbl_create_osi_method)
+                return;
+
+        if (str == NULL || *str == '\0') {
+                printk(KERN_INFO PREFIX "_OSI method disabled\n");
+                acpi_gbl_create_osi_method = FALSE;
+        } else
+                strncpy(osi_setup_string, str, OSI_STRING_LENGTH_MAX);
+}
+
 static void __init set_osi_linux(unsigned int enable)
 {
-        if (osi_linux.enable != enable) {
+        if (osi_linux.enable != enable)
                 osi_linux.enable = enable;
-                printk(KERN_NOTICE PREFIX "%sed _OSI(Linux)\n",
-                        enable ? "Add": "Delet");
-        }
 
         if (osi_linux.enable)
                 acpi_osi_setup("Linux");
@@ -1073,7 +1081,8 @@ static void __init set_osi_linux(unsigned int enable)
 
 static void __init acpi_cmdline_osi_linux(unsigned int enable)
 {
-        osi_linux.cmdline = 1;  /* cmdline set the default */
+        osi_linux.cmdline = 1;  /* cmdline set the default and override DMI */
+        osi_linux.dmi = 0;
         set_osi_linux(enable);
 
         return;
@@ -1081,15 +1090,12 @@ static void __init acpi_cmdline_osi_linux(unsigned int enable)
 
 void __init acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d)
 {
-        osi_linux.dmi = 1;      /* DMI knows that this box asks OSI(Linux) */
-
         printk(KERN_NOTICE PREFIX "DMI detected: %s\n", d->ident);
 
         if (enable == -1)
                 return;
 
-        osi_linux.known = 1;    /* DMI knows which OSI(Linux) default needed */
-
+        osi_linux.dmi = 1;      /* DMI knows that this box asks OSI(Linux) */
         set_osi_linux(enable);
 
         return;
@@ -1105,36 +1111,37 @@ void __init acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d)
 static void __init acpi_osi_setup_late(void)
 {
         char *str = osi_setup_string;
+        acpi_status status;
 
         if (*str == '\0')
                 return;
 
-        if (!strcmp("!Linux", str)) {
-                acpi_cmdline_osi_linux(0);      /* !enable */
-        } else if (*str == '!') {
-                if (acpi_remove_interface(++str) == AE_OK)
+        if (*str == '!') {
+                status = acpi_remove_interface(++str);
+
+                if (ACPI_SUCCESS(status))
                         printk(KERN_INFO PREFIX "Deleted _OSI(%s)\n", str);
-        } else if (!strcmp("Linux", str)) {
-                acpi_cmdline_osi_linux(1);      /* enable */
         } else {
-                if (acpi_install_interface(str) == AE_OK)
+                status = acpi_install_interface(str);
+
+                if (ACPI_SUCCESS(status))
                         printk(KERN_INFO PREFIX "Added _OSI(%s)\n", str);
         }
 }
 
-int __init acpi_osi_setup(char *str)
+static int __init osi_setup(char *str)
 {
-        if (str == NULL || *str == '\0') {
-                printk(KERN_INFO PREFIX "_OSI method disabled\n");
-                acpi_gbl_create_osi_method = FALSE;
-        } else {
-                strncpy(osi_setup_string, str, OSI_STRING_LENGTH_MAX);
-        }
+        if (str && !strcmp("Linux", str))
+                acpi_cmdline_osi_linux(1);
+        else if (str && !strcmp("!Linux", str))
+                acpi_cmdline_osi_linux(0);
+        else
+                acpi_osi_setup(str);
 
         return 1;
 }
 
-__setup("acpi_osi=", acpi_osi_setup);
+__setup("acpi_osi=", osi_setup);
 
 /* enable serialization to combat AE_ALREADY_EXISTS errors */
 static int __init acpi_serialize_setup(char *str)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 050a7bccb836..67c91b4418b0 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -219,7 +219,7 @@ static inline int acpi_video_display_switch_support(void)
 
 extern int acpi_blacklisted(void);
 extern void acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d);
-extern int acpi_osi_setup(char *str);
+extern void acpi_osi_setup(char *str);
 
 #ifdef CONFIG_ACPI_NUMA
 int acpi_get_pxm(acpi_handle handle);