Messages in this thread Patch in this message | | | From | Eric Miao <> | Date | Sun, 24 Jun 2012 23:32:38 +0800 | Subject | [PATCH RFC] input: fix weird issue of synaptics psmouse sync lost after resume |
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All,
BugLink: https://bugs.launchpad.net/bugs/717970
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 reproduced.
There are two PS/2 commands in psmouse_probe():
1. PSMOUSE_CMD_GETID 2. PSMOUSE_CMD_RESET_DIS
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.
========= >8 =========
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c index 8eac3b7..7a72d82 100644 --- a/drivers/input/mouse/synaptics.c +++ b/drivers/input/mouse/synaptics.c @@ -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[2]; int retry = 0; int error;
@@ -1233,6 +1234,7 @@ 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);
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