[PATCH V3] input: Default to only using PNP for i8042 probing on x86

[Matthew Garrett <mjg@redhat.com>]

Experimenting with Windows has revealed that it will not probe the
keyboard controller unless a valid PNPACPI device is present. Change our
behaviour to match - users can override by using the existing
i8042.nopnp=1 parameter.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/input/serio/i8042-x86ia64io.h |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/input/serio/i8042-x86ia64io.h b/drivers/input/serio/i8042-x86ia64io.h
index 6168469..19d11f3 100644
--- a/drivers/input/serio/i8042-x86ia64io.h
+++ b/drivers/input/serio/i8042-x86ia64io.h
@@ -1,6 +1,8 @@
 #ifndef _I8042_X86IA64IO_H
 #define _I8042_X86IA64IO_H
 
+#include <linux/acpi.h>
+
 /*
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
@@ -744,12 +746,16 @@ static int __init i8042_pnp_init(void)
 
 	if (!i8042_pnp_kbd_devices && !i8042_pnp_aux_devices) {
 		i8042_pnp_exit();
-#if defined(__ia64__)
-		return -ENODEV;
-#else
+
+		/* Non-ACPI systems are much less likely to have the
+		 * KBC declared via PNP, so if acpi is disabled fall
+		 * back to banging the ports directly */
+
+		if (!acpi_disabled)
+			return -ENODEV;
+
 		printk(KERN_INFO "PNP: No PS/2 controller found. Probing ports directly.\n");
 		return 0;
-#endif
 	}
 
 	if (i8042_pnp_kbd_devices)
-- 
1.7.0.1