From 1b6521dc84f372dd92a96381fbeeebb01173d050 Mon Sep 17 00:00:00 2001
From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Date: Sun, 23 Sep 2007 11:39:03 -0300
Subject: ACPI: thinkpad-acpi: check version of hot key firmware

Check the HKEY firmware version (HKEY.MHKV handler), and refuse to load if
it is unknown.  Use this instead of the presence of HKEY.DHKV to detect hot
key mask capability.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 2155139..9a61140 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -999,6 +999,7 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 
 	int res, i;
 	int status;
+	int hkeyv;
 
 	vdbg_printk(TPACPI_DBG_INIT, "initializing hotkey subdriver\n");
 
@@ -1024,18 +1025,35 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 			return res;
 
 		/* mask not supported on 570, 600e/x, 770e, 770x, A21e, A2xm/p,
-		   A30, R30, R31, T20-22, X20-21, X22-24 */
-		tp_features.hotkey_mask =
-			acpi_evalf(hkey_handle, NULL, "DHKN", "qv");
+		   A30, R30, R31, T20-22, X20-21, X22-24.  Detected by checking
+		   for HKEY interface version 0x100 */
+		if (acpi_evalf(hkey_handle, &hkeyv, "MHKV", "qd")) {
+			if ((hkeyv >> 8) != 1) {
+				printk(IBM_ERR "unknown version of the "
+				       "HKEY interface: 0x%x\n", hkeyv);
+				printk(IBM_ERR "please report this to %s\n",
+				       IBM_MAIL);
+			} else {
+				/*
+				 * MHKV 0x100 in A31, R40, R40e,
+				 * T4x, X31, and later
+				 * */
+				tp_features.hotkey_mask = 1;
+			}
+		}
 
 		vdbg_printk(TPACPI_DBG_INIT, "hotkey masks are %s\n",
 			str_supported(tp_features.hotkey_mask));
 
 		if (tp_features.hotkey_mask) {
-			/* MHKA available in A31, R40, R40e, T4x, X31, and later */
 			if (!acpi_evalf(hkey_handle, &hotkey_all_mask,
-					"MHKA", "qd"))
+					"MHKA", "qd")) {
+				printk(IBM_ERR
+				       "missing MHKA handler, "
+				       "please report this to %s\n",
+				       IBM_MAIL);
 				hotkey_all_mask = 0x080cU; /* FN+F12, FN+F4, FN+F3 */
+			}
 		}
 
 		res = hotkey_get(&hotkey_orig_status, &hotkey_orig_mask);
-- 
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