Commit eeb06558 authored Jun 04, 2013 by Eric Miao Committed by Dmitry Torokhov Jun 04, 2013

Input: synaptics - fix sync lost after resume on some laptops



In summary, the symptom is intermittent key events lost after resume
on some machines with synaptics touchpad (seems this is synaptics _only_),
and key events loss is due to serio port reconnect after psmouse sync lost.
Removing psmouse and inserting it back during the suspend/resume process
is able to work around the issue, so the difference between psmouse_connect()
and psmouse_reconnect() is the key to the root cause of this problem.

After comparing the two different paths, synaptics driver has its own
implementation of synaptics_reconnect(), and the missing psmouse_probe()
seems significant, the patch below added psmouse_probe() to the reconnect
process, and has been verified many times that the issue could not be reliably
reproduced.

There are two PS/2 commands in psmouse_probe():

  1. PSMOUSE_CMD_GETID
  2. PSMOUSE_CMD_RESET_DIS

Only the PSMOUSE_CMD_GETID seems to be significant. The
PSMOUSE_CMD_RESET_DIS is irrelevant to this issue after trying
several times.  So we have only implemented this patch to issue
the PSMOUSE_CMD_GETID so far.

Tested-by: Daniel Manrique <daniel.manrique@canonical.com>
Signed-off-by: James M Leddy <james.leddy@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

parent c73a1afb

drivers/input/mouse/synaptics.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1379,6 +1379,7 @@ static int synaptics_reconnect(struct psmouse *psmouse)
		{
		struct synaptics_data *priv = psmouse->private;
		struct synaptics_data old_priv = *priv;
		unsigned char param[2];
		int retry = 0;
		int error;

		@@ -1394,6 +1395,7 @@ static int synaptics_reconnect(struct psmouse *psmouse)
		*/
		ssleep(1);
		}
		ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETID);
		error = synaptics_detect(psmouse, 0);
		} while (error && ++retry < 3);