dell-wmi: properly process Dell Instant Launch hotkey

On models on which an SMBIOS request needs to be issued in order for WMI
events to be generated, pressing the Dell Instant Launch hotkey does not
raise an i8042 interrupt - only a WMI event is generated (0xe025 on Dell
Vostro V131).  As that WMI event is the only way the kernel will be
notified about pressing the Dell Instant Launch hotkey on such machines,
the relevant keymap entry has to be changed to a KE_KEY one.  However,
the same WMI event should still be ignored on machines which do not
require an SMBIOS request for enabling WMI, so filter it conditionally
in dell_wmi_process_key().

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

drivers/platform/x86/dell-wmi.c

@@ -111,7 +111,7 @@ 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 } },
@@ -235,6 +235,9 @@ static void dell_wmi_process_key(int reported_key)
 	    acpi_video_handles_brightness_key_presses())
 		return;
 
+	if (reported_key == 0xe025 && !wmi_requires_smbios_request)
+		return;
+
 	sparse_keymap_report_entry(dell_wmi_input_dev, key, 1, true);
 }