[PATCH] input: Force Sentelic reconnect when mode setting has failed

[Matthew Garrett <mjg@redhat.com>]

The Sentelic touchpad in an Asus UX-21 failed to work since the native
driver was merged. Examination showed that the FSP_REG_SWC1 register had
reverted back to 0x80 and so the pad was sending normal packets despite
the driver expecting absolute ones.

I haven't been able to identify what causes this - dumping the register
state after ps2 setup shows it set correctly. The easiest workaround seems
to be to force a reconnect when an unexpected packet type is received.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/input/mouse/sentelic.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/input/mouse/sentelic.c b/drivers/input/mouse/sentelic.c
index 661a0ca..aaabf94 100644
--- a/drivers/input/mouse/sentelic.c
+++ b/drivers/input/mouse/sentelic.c
@@ -687,7 +687,7 @@ static psmouse_ret_t fsp_process_byte(struct psmouse *psmouse)
 	unsigned char *packet = psmouse->packet;
 	unsigned char button_status = 0, lscroll = 0, rscroll = 0;
 	unsigned short abs_x, abs_y, fgrs = 0;
-	int rel_x, rel_y;
+	int rel_x, rel_y, packet_type;
 
 	if (psmouse->pktcnt < 4)
 		return PSMOUSE_GOOD_DATA;
@@ -698,7 +698,17 @@ static psmouse_ret_t fsp_process_byte(struct psmouse *psmouse)
 
 	fsp_packet_debug(psmouse, packet);
 
-	switch (psmouse->packet[0] >> FSP_PKT_TYPE_SHIFT) {
+	packet_type = psmouse->packet[0] >> FSP_PKT_TYPE_SHIFT;
+
+	if (ad->ver >= FSP_VER_STL3888_C0 && packet_type != FSP_PKT_TYPE_ABS) {
+		psmouse_warn(psmouse,
+			     "Incorrect packet type %x, reconnecting\n",
+			     packet_type);
+		serio_reconnect(psmouse->ps2dev.serio);
+		return PSMOUSE_FULL_PACKET;
+	}
+
+	switch (packet_type) {
 	case FSP_PKT_TYPE_ABS:
 		abs_x = GET_ABS_X(packet);
 		abs_y = GET_ABS_Y(packet);
-- 
1.7.9.5