Input: i8042 - introduce a tougher reset

Some touchpads don't reset right the first time (MSI Wind U-100 for
example).  This patch will retry the reset up to 5 times.

In addition, on x86, we don't fail entire i8042 initialization if
controller reset fails in hope that keyboard port will still be
functional and user will still get a working keyboard. This is
especially important on netbooks.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 170f71e..3cffb70 100644 (file)
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -712,22 +712,43 @@ static int i8042_controller_check(void)
 static int i8042_controller_selftest(void)
 {
        unsigned char param;
+       int i = 0;
 
        if (!i8042_reset)
                return 0;
 
-       if (i8042_command(&param, I8042_CMD_CTL_TEST)) {
-               printk(KERN_ERR "i8042.c: i8042 controller self test timeout.\n");
-               return -ENODEV;
-       }
+       /*
+        * We try this 5 times; on some really fragile systems this does not
+        * take the first time...
+        */
+       do {
+
+               if (i8042_command(&param, I8042_CMD_CTL_TEST)) {
+                       printk(KERN_ERR "i8042.c: i8042 controller self test timeout.\n");
+                       return -ENODEV;
+               }
+
+               if (param == I8042_RET_CTL_TEST)
+                       return 0;
 
-       if (param != I8042_RET_CTL_TEST) {
                printk(KERN_ERR "i8042.c: i8042 controller selftest failed. (%#x != %#x)\n",
-                        param, I8042_RET_CTL_TEST);
-               return -EIO;
-       }
+                       param, I8042_RET_CTL_TEST);
+               msleep(50);
+       } while (i++ < 5);
 
+#ifdef CONFIG_X86
+       /*
+        * On x86, we don't fail entire i8042 initialization if controller
+        * reset fails in hopes that keyboard port will still be functional
+        * and user will still get a working keyboard. This is especially
+        * important on netbooks. On other arches we trust hardware more.
+        */
+       printk(KERN_INFO
+               "i8042: giving up on controller selftest, continuing anyway...\n");
        return 0;
+#else
+       return -EIO;
+#endif
 }
 
 /*