x86: Fix "Acer Aspire 1" reboot hang

Looks like on some Acer Aspire 1s with older bioses, reboot via bios
fails.  It works on my machine, (with BIOS version 0.3310) but
not on some others (BIOS version 0.3309).

There's a log of problems at:

  https://bbs.archlinux.org/viewtopic.php?id=124136

This patch adds a different callback to the reboot quirk table,
to allow rebooting via keybaord controller.

Reported-by: Uroš Vampl <mobile.leecher@gmail.com>
Tested-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1323093233-9481-1-git-send-email-anarsoul@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/reboot.c

@@ -124,7 +124,7 @@ __setup("reboot=", reboot_setup);
  */
 
 /*
- * Some machines require the "reboot=b"  commandline option,
+ * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  * this quirk makes that automatic.
  */
 static int __init set_bios_reboot(const struct dmi_system_id *d)
@@ -136,6 +136,15 @@ static int __init set_bios_reboot(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init set_kbd_reboot(const struct dmi_system_id *d)
+{
+	if (reboot_type != BOOT_KBD) {
+		reboot_type = BOOT_KBD;
+		printk(KERN_INFO "%s series board detected. Selecting KBD-method for reboot.\n", d->ident);
+	}
+	return 0;
+}
+
 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 	{	/* Handle problems with rebooting on Dell E520's */
 		.callback = set_bios_reboot,
@@ -295,7 +304,7 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
 		},
 	},
 	{ /* Handle reboot issue on Acer Aspire one */
-		.callback = set_bios_reboot,
+		.callback = set_kbd_reboot,
 		.ident = "Acer Aspire One A110",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),