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>

1 files changed, 29 insertions, 8 deletions

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 170f71ee5772..3cffb704e374 100644
--- 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
 }
 
 /*