Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 17ec1c6b authored by Phoenix Huang's avatar Phoenix Huang Committed by Greg Kroah-Hartman
Browse files

Input: elantench - fix misreporting trackpoint coordinates 



commit be896bd3b72b44126c55768f14c22a8729b0992e upstream.

Some firmwares occasionally report bogus data from trackpoint, with X or Y
displacement being too large (outside of [-127, 127] range). Let's drop such
packets so that we do not generate jumps.

Signed-off-by: default avatarPhoenix Huang <phoenix@emc.com.tw>
Tested-by: default avatarYufei Du <yufeidu@cs.unc.edu>
Link: https://lore.kernel.org/r/20210729010940.5752-1-phoenix@emc.com.tw


Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ce4bec0a

drivers/input/mouse/elantech.c

+13 −0
Original line number Diff line number Diff line
@@ -517,6 +517,19 @@ static void elantech_report_trackpoint(struct psmouse *psmouse, 
	case 0x16008020U:

	case 0x26800010U:

	case 0x36808000U:



		/*

		 * This firmware misreport coordinates for trackpoint

		 * occasionally. Discard packets outside of [-127, 127] range

		 * to prevent cursor jumps.

		 */

		if (packet[4] == 0x80 || packet[5] == 0x80 ||

		    packet[1] >> 7 == packet[4] >> 7 ||

		    packet[2] >> 7 == packet[5] >> 7) {

			elantech_debug("discarding packet [%6ph]\n", packet);

			break;



		}

		x = packet[4] - (int)((packet[1]^0x80) << 1);

		y = (int)((packet[2]^0x80) << 1) - packet[5];