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

…inux/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

Documentation/x86/boot.txt

@@ -373,14 +373,15 @@ Protocol:	2.00+
 	1  Loadlin
 	2  bootsect-loader	(0x20, all other values reserved)
 	3  Syslinux
-	4  Etherboot/gPXE
+	4  Etherboot/gPXE/iPXE
 	5  ELILO
 	7  GRUB
 	8  U-Boot
 	9  Xen
 	A  Gujin
 	B  Qemu
 	C  Arcturus Networks uCbootloader
+	D  kexec-tools
 	E  Extended		(see ext_loader_type)
 	F  Special		(0xFF = undefined)
        10  Reserved

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;