So 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
There are two PS/2 commands in psmouse_probe():
The weird thing is, the PSMOUSE_CMD_GETID seems to be significant, and the
PSMOUSE_CMD_RESET_DIS is irrelevant to this issue after trying several times.
Now it's rather difficult to form a sane theory. So this patch is
really for RFC.
Note it does fix a real problem though.
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 8eac3b7..7a72d82 100644
@@ -1218,6 +1218,7 @@ static int synaptics_reconnect(struct psmouse *psmouse)
struct synaptics_data *priv = psmouse->private;
struct synaptics_data old_priv = *priv;
+ unsigned char param;
int retry = 0;
@@ -1233,6 +1234,7 @@ static int synaptics_reconnect(struct psmouse *psmouse)
+ ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETID);
error = synaptics_detect(psmouse, 0);
} while (error && ++retry < 3);
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to email@example.com
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/