Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull small x86 fixes from Peter Anvin:
 "A collection of very small fixes, mostly pure documentation."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, doc: Document that bootloader ID 4 is used also by iPXE
  x86, doc: Add a formal bootloader ID for kexec-tools
  x86, 8042: Enable A20 using KBC to fix S3 resume on some MSI laptops

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/input/serio/i8042-x86ia64io.h b/drivers/input/serio/i8042-x86ia64io.h
index d6cc77a53c7e..5f306f79da0c 100644
--- a/drivers/input/serio/i8042-x86ia64io.h
+++ b/drivers/input/serio/i8042-x86ia64io.h
@@ -921,6 +921,7 @@ static int __init i8042_platform_init(void)
         int retval;
 
 #ifdef CONFIG_X86
+        u8 a20_on = 0xdf;
         /* Just return if pre-detection shows no i8042 controller exist */
         if (!x86_platform.i8042_detect())
                 return -ENODEV;
@@ -960,6 +961,14 @@ static int __init i8042_platform_init(void)
 
         if (dmi_check_system(i8042_dmi_dritek_table))
                 i8042_dritek = true;
+
+        /*
+         * A20 was already enabled during early kernel init. But some buggy
+         * BIOSes (in MSI Laptops) require A20 to be enabled using 8042 to
+         * resume from S3. So we do it here and hope that nothing breaks.
+         */
+        i8042_command(&a20_on, 0x10d1);
+        i8042_command(NULL, 0x00ff);    /* Null command for SMM firmware */
 #endif /* CONFIG_X86 */
 
         return retval;