[PATCH] dell-wmi: add module param to control Dell Instant Launch hotkey processing

["Michał Kępień" <kernel@kempniu.pl>]

On some laptop models (e.g. Dell Vostro V131), pressing the Dell Instant
Launch hotkey does not raise an i8042 interrupt - only WMI event 0xe025
is generated.  As there is no flawless way to determine whether a given
machine is capable of simulating a keypress when this hotkey is pressed,
a new module parameter is added so that the user can decide whether the
WMI event should be processed or ignored.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
---
As my last message [1] in the rather lengthy thread failed to elicit any
response, I guess I might just as well post the proposed patch so that
we have something specific to discuss.

[1] http://www.spinics.net/lists/platform-driver-x86/msg07679.html

 drivers/platform/x86/dell-wmi.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 8cb0f57..e68ce3b 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -44,6 +44,10 @@ MODULE_LICENSE("GPL");
 #define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
 
 static int acpi_video;
+static bool process_dil;
+
+module_param(process_dil, bool, 0644);
+MODULE_PARM_DESC(process_dil, "Generate an input event when the WMI event for Dell Instant Launch hotkey is received");
 
 MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
 
@@ -87,7 +91,7 @@ static const struct key_entry dell_wmi_legacy_keymap[] __initconst = {
 	{ KE_IGNORE, 0xe020, { KEY_MUTE } },
 
 	/* Shortcut and audio panel keys */
-	{ KE_IGNORE, 0xe025, { KEY_RESERVED } },
+	{ KE_KEY, 0xe025, { KEY_PROG4 } },
 	{ KE_IGNORE, 0xe026, { KEY_RESERVED } },
 
 	{ KE_IGNORE, 0xe02e, { KEY_VOLUMEDOWN } },
@@ -183,6 +187,9 @@ static void dell_wmi_process_key(int reported_key)
 	     key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video)
 		return;
 
+	if (key->keycode == KEY_PROG4 && !process_dil)
+		return;
+
 	sparse_keymap_report_entry(dell_wmi_input_dev, key, 1, true);
 }
 
-- 
1.7.10.4