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>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index c080b828e5dc..a6dcd18e9adf 100644
--- 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);