Input: cypress_ps2 - do not consider data bad if palm is detected

If hardware (or firmware) detects palm on the surface of the device it does
not mean that the data packet is bad from the protocol standpoint. Instead
of reporting PSMOUSE_BAD_DATA in this case simply threat it as if nothing
touches the surface.

BugLink: http://bugs.launchpad.net/bugs/1229361

Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Tested-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/cypress_ps2.c

@@ -439,7 +439,7 @@ static int cypress_get_finger_count(unsigned char header_byte)
 			case 2: return 5;
 			default:
 				/* Invalid contact (e.g. palm). Ignore it. */
-				return -1;
+				return 0;
 		}
 	}
 
@@ -452,17 +452,10 @@ static int cypress_parse_packet(struct psmouse *psmouse,
 {
 	unsigned char *packet = psmouse->packet;
 	unsigned char header_byte = packet[0];
-	int contact_cnt;
 
 	memset(report_data, 0, sizeof(struct cytp_report_data));
 
-	contact_cnt = cypress_get_finger_count(header_byte);
-
-	if (contact_cnt < 0) /* e.g. palm detect */
-		return -EINVAL;
-
-	report_data->contact_cnt = contact_cnt;
-
+	report_data->contact_cnt = cypress_get_finger_count(header_byte);
 	report_data->tap = (header_byte & ABS_MULTIFINGER_TAP) ? 1 : 0;
 
 	if (report_data->contact_cnt == 1) {
@@ -535,11 +528,9 @@ static void cypress_process_packet(struct psmouse *psmouse, bool zero_pkt)
 	int slots[CYTP_MAX_MT_SLOTS];
 	int n;
 
-	if (cypress_parse_packet(psmouse, cytp, &report_data))
-		return;
+	cypress_parse_packet(psmouse, cytp, &report_data);
 
 	n = report_data.contact_cnt;
-
 	if (n > CYTP_MAX_MT_SLOTS)
 		n = CYTP_MAX_MT_SLOTS;
 
@@ -605,10 +596,6 @@ static psmouse_ret_t cypress_validate_byte(struct psmouse *psmouse)
 		return PSMOUSE_BAD_DATA;
 
 	contact_cnt = cypress_get_finger_count(packet[0]);
-
-	if (contact_cnt < 0)
-		return PSMOUSE_BAD_DATA;
-
 	if (cytp->mode & CYTP_BIT_ABS_NO_PRESSURE)
 		cypress_set_packet_size(psmouse, contact_cnt == 2 ? 7 : 4);
 	else