From: Eric Miao <eric.m...@canonical.com>
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.manri...@canonical.com>
Signed-off-by: James M Leddy <james.le...@canonical.com>
---
drivers/input/mouse/synaptics.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/input/mouse/synaptics.c
b/drivers/input/mouse/synaptics.c
index 12d12ca..3438a9d 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -1355,6 +1355,7 @@ 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;
@@ -1370,6 +1371,7 @@ 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);
-- 1.7.9.5
