dummy-irq: introduce a dummy IRQ handler driver

This module accepts a single 'irq' parameter, which it should register for.

Its sole purpose is to help with debugging of IRQ sharing problems, by
force-enabling IRQ that would otherwise be disabled.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index e83fdfe..69bb79d 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -93,6 +93,14 @@
 	  TC can be used for other purposes, such as PWM generation and
 	  interval timing.
 
+config DUMMY_IRQ
+	tristate "Dummy IRQ handler"
+	default n
+	---help---
+	  This module accepts a single 'irq' parameter, which it should register for.
+	  The sole purpose of this module is to help with debugging of systems on
+	  which spurious IRQs would happen on disabled IRQ vector.
+
 config IBM_ASM
 	tristate "Device driver for IBM RSA service processor"
 	depends on X86 && PCI && INPUT