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

commit 8521478f67e95ada4e87970c7b41e504c724b2cf upstream.

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>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 5538fc657af176b265cda6178dad06e0e8b51705..767536372181cf23e4981933959cec7c0320c0ee 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>
@@ -786,6 +787,16 @@ 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);