[PATCH] Input: psmouse - add small delay for IBM trackpoint pass-through mode

From: Stefan Assmann
Date: Sat Aug 15 2015 - 10:50:23 EST

There are trackpoint devices that fail to respond to the PS2 command
PSMOUSE_CMD_GETID if immediately queried after the parent device is
deactivated. Add a small delay for the hardware to get in a sane state
before sending any PS2 commands.

One example of such a system is:
Lenovo ThinkPad X120e, model 30515QG
synaptics: Touchpad model: 1, fw: 8.0, id: 0x1e2b1, caps: 0xd001a3/0x940300/0x121c00, board id: 1811, fw id: 797391

Signed-off-by: Stefan Assmann <sassmann@xxxxxxxxx>
drivers/input/mouse/psmouse-base.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index ec347703..ad18dab 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -1540,6 +1540,10 @@ static int psmouse_connect(struct serio *serio, struct serio_driver *drv)
if (error)
goto err_clear_drvdata;

+ /* give PT device some time to settle down before probing */
+ if (serio->id.type == SERIO_PS_PSTHRU)
+ usleep_range(10000, 15000);
if (psmouse_probe(psmouse) < 0) {
error = -ENODEV;
goto err_close_serio;

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