platform/x86: thinkpad_acpi: guard generic hotkey case

BugLink: http://bugs.launchpad.net/bugs/1705169

Currently when dispatching hotkeys we check if the scancode is in
the range of 0 and TPACPI_HOTKEY_MAP_LEN, although the bottom 20
entries in the hotkey keymap are already adaptive keycodes.
Therefore we introduce a TP_ACPI_HOTKEYSCAN_ADAPTIVE_START and
ensure that we are in the range 0 and ADAPTIVE_START for the generic
keycode case.
Signed-off-by: Christian Kellner <ckellner@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
(cherry picked from commit 149c8c75)
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Acked-by: Hui Wang &lt;Wang <hui.wang@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/platform/x86/thinkpad_acpi.c

@@ -1915,7 +1915,9 @@ enum {	/* hot key scan codes (derived from ACPI DSDT) */
 	TP_ACPI_HOTKEYSCAN_UNK7,
 	TP_ACPI_HOTKEYSCAN_UNK8,
 
-	TP_ACPI_HOTKEYSCAN_MUTE2,
+	/* Adaptive keyboard keycodes */
+	TP_ACPI_HOTKEYSCAN_ADAPTIVE_START,
+	TP_ACPI_HOTKEYSCAN_MUTE2        = TP_ACPI_HOTKEYSCAN_ADAPTIVE_START,
 	TP_ACPI_HOTKEYSCAN_BRIGHTNESS_ZERO,
 	TP_ACPI_HOTKEYSCAN_CLIPPING_TOOL,
 	TP_ACPI_HOTKEYSCAN_CLOUD,
@@ -3610,7 +3612,6 @@ static const int adaptive_keyboard_modes[] = {
 #define DFR_CHANGE_ROW			0x101
 #define DFR_SHOW_QUICKVIEW_ROW		0x102
 #define FIRST_ADAPTIVE_KEY		0x103
-#define ADAPTIVE_KEY_OFFSET		0x020
 
 /* press Fn key a while second, it will switch to Function Mode. Then
  * release Fn key, previous mode be restored.
@@ -3701,12 +3702,13 @@ static bool adaptive_keyboard_hotkey_notify_hotkey(unsigned int scancode)
 	default:
 		if (scancode < FIRST_ADAPTIVE_KEY ||
 		    scancode >= FIRST_ADAPTIVE_KEY + TPACPI_HOTKEY_MAP_LEN -
-				ADAPTIVE_KEY_OFFSET) {
+				TP_ACPI_HOTKEYSCAN_ADAPTIVE_START) {
 			pr_info("Unhandled adaptive keyboard key: 0x%x\n",
 					scancode);
 			return false;
 		}
-		keycode = hotkey_keycode_map[scancode - FIRST_ADAPTIVE_KEY + ADAPTIVE_KEY_OFFSET];
+		keycode = hotkey_keycode_map[scancode - FIRST_ADAPTIVE_KEY +
+					     TP_ACPI_HOTKEYSCAN_ADAPTIVE_START];
 		if (keycode != KEY_RESERVED) {
 			mutex_lock(&tpacpi_inputdev_send_mutex);
 
@@ -3732,7 +3734,7 @@ static bool hotkey_notify_hotkey(const u32 hkey,
 	*ignore_acpi_ev = false;
 
 	/* HKEY event 0x1001 is scancode 0x00 */
-	if (scancode > 0 && scancode <= TPACPI_HOTKEY_MAP_LEN) {
+	if (scancode > 0 && scancode <= TP_ACPI_HOTKEYSCAN_ADAPTIVE_START) {
 		scancode--;
 		if (!(hotkey_source_mask & (1 << scancode))) {
 			tpacpi_input_send_key_masked(scancode);