Input: synaptics - fix touchpad not working after S2R on Vostro V13

Synaptics touchpads on several Dell laptops, particularly Vostro V13
systems, may not respond properly to PS/2 commands and queries immediately
after resuming from suspend to RAM. This leads to unresponsive touchpad
after suspend/resume cycle.

Adding a 1-second delay after resetting the device allows touchpad to
finish initializing (calibrating?) and start reacting properly.

Reported-by: Daniel Manrique <daniel.manrique@canonical.com>
Tested-by: Daniel Manrique <daniel.manrique@canonical.com>
Cc: stable@kernel.org
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index c080b828e5dc5e2f69c8cf859deebe3d6abbae61..a6dcd18e9adf93b5b97cd00e04b6419a6788e1e5 100644 (file)
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -24,6 +24,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/delay.h>
 #include <linux/dmi.h>
 #include <linux/input/mt.h>
 #include <linux/serio.h>
@@ -1220,6 +1221,16 @@ static int synaptics_reconnect(struct psmouse *psmouse)
 
        do {
                psmouse_reset(psmouse);
+               if (retry) {
+                       /*
+                        * On some boxes, right after resuming, the touchpad
+                        * needs some time to finish initializing (I assume
+                        * it needs time to calibrate) and start responding
+                        * to Synaptics-specific queries, so let's wait a
+                        * bit.
+                        */
+                       ssleep(1);
+               }
                error = synaptics_detect(psmouse, 0);
        } while (error && ++retry < 3);