ps/2 elantech: v3 support (untested)

Trackpoint related packets are ignored as of now. Packet description and validations based on FreeBSD 14.3 psm driver. Packet processing code based on OpenBSD 7.8 pms driver with variable naming adjustments to match FreeBSD and Haiku. Excluded v3 faulty devices as described on Linux ETPS/2 driver. Change-Id: I5493128557b72fe72f0ea72e225854b745da459a Reviewed-on: https://review.haiku-os.org/c/haiku/+/9953 Tested-by: Commit checker robot <[email protected]> Reviewed-by: Adrien Destugues <[email protected]>
2026-01-02 11:01:29 +00:00
parent 42c5c30bc7
commit 35e407488a
1 changed files with 119 additions and 1 deletions
@@ -79,6 +79,9 @@ const char* kElantechPath[4] = {
 static touchpad_specs gHardwareSpecs;


+static status_t
+elantech_process_packet_v3(elantech_cookie *cookie, touchpad_movement *_event,
+	uint8 packet[PS2_PACKET_ELANTECH]);
 static status_t
 elantech_process_packet_v4(elantech_cookie *cookie, touchpad_movement *_event,
 	uint8 packet[PS2_PACKET_ELANTECH]);
@@ -114,7 +117,117 @@ get_elantech_movement(elantech_cookie *cookie, touchpad_movement *_event, bigtim
 		return B_ERROR;
 	}

-	return elantech_process_packet_v4(cookie, _event, packet);
+	if ((cookie->capabilities[0] & 0x80) != 0 && (packet[3] & 0x0f) == 0x06) {
+		status = IGNORE_EVENT;
+	} else {
+		switch (cookie->version) {
+			case 3:
+				status = elantech_process_packet_v3(cookie, _event, packet);
+				break;
+			case 4:
+				status = elantech_process_packet_v4(cookie, _event, packet);
+				break;
+			default:
+				TRACE("ELANTECH: Unknown version %d.\n", cookie->version);
+				return B_ERROR;
+		}
+	}
+	return status;
+}
+
+
+static status_t
+elantech_process_packet_v3(elantech_cookie *cookie, touchpad_movement *_event,
+	uint8 packet[PS2_PACKET_ELANTECH])
+{
+	/*               7   6   5   4   3   2   1   0 (LSB)
+	 * -------------------------------------------
+	 * ipacket[0]:  N1  N0  W3  W2   0   1   R   L
+	 * ipacket[1]:  P7  P6  P5  P4 X11 X10  X9  X8
+	 * ipacket[2]:  X7  X6  X5  X4  X3  X2  X1  X0
+	 * ipacket[3]:   0   0  W1  W0   0   0   1   0
+	 * ipacket[4]:  P3  P1  P2  P0 Y11 Y10  Y9  Y8
+	 * ipacket[5]:  Y7  Y6  Y5  Y4  Y3  Y2  Y1  Y0
+	 * -------------------------------------------
+	 */
+
+	// Validation based on FreeBSD psm.c driver.
+	bool valid;
+	valid = false;
+	if (cookie->crcEnabled) {
+		if ((packet[3] & 0x09) == 0x08 || (packet[3] & 0xcf) == 0x02)
+			valid = true;
+	} else if (((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
+				|| ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c))
+		valid = true;
+
+	if (!valid)
+		return IGNORE_EVENT;
+
+	const uint8 debounce_pkt[] = { 0xc4, 0xff, 0xff, 0x02, 0xff, 0xff };
+	uint32 x, y;
+	uint8 n, w, z;
+	uint8 buttons;
+
+	buttons = packet[0] & 3;
+
+	x = ((packet[1] & 0x0f) << 8 | packet[2]);
+	y = ((packet[4] & 0x0f) << 8 | packet[5]);
+	z = 0;
+	n = (packet[0] & 0xc0) >> 6;
+	if (n == 2) {
+		/*
+		 * Two-finger touch causes two packets -- a head packet
+		 * and a tail packet. We report a single event and ignore
+		 * the tail packet.
+		 */
+		if (cookie->crcEnabled) {
+			if ((packet[3] & 0x09) != 0x08)
+				return IGNORE_EVENT;
+		} else {
+			/* The hardware sends this packet when in debounce state.
+			 * The packet should be ignored. */
+			if (!memcmp(packet, debounce_pkt, sizeof(debounce_pkt)))
+				return IGNORE_EVENT;
+			if ((packet[0] & 0x0c) != 0x04 &&
+				(packet[3] & 0xcf) != 0x02) {
+				/* not the head packet -- ignore */
+				return IGNORE_EVENT;
+			}
+		}
+	}
+
+	/* Prevent jumping cursor if pad isn't touched or reports garbage. */
+	if (n == 0 ||
+		((x == 0 || y == 0 || x == gHardwareSpecs.areaEndX || y == gHardwareSpecs.areaEndY)
+		&& (x != cookie->x || y != cookie->y))) {
+		x = cookie->x;
+		y = cookie->y;
+	}
+
+	if (cookie->fwVersion >= 0x020800)
+		z = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
+	else if (n)
+		z = DEFAULT_PRESSURE;
+
+	w = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
+
+	cookie->x = x;
+	cookie->y = y;
+
+	touchpad_movement event = {
+		.buttons = buttons,
+		.xPosition = x,
+		.yPosition = y,
+		.zPressure = z,
+		//.nFingers = n,
+		.fingers = (uint8)((1 << n) - 1),
+		.fingerWidth = w,
+	};
+
+	*_event = event;
+
+	return B_OK;
 }


@@ -805,6 +918,11 @@ elantech_open(const char *name, uint32 flags, void **_cookie)
 			TRACE("ELANTECH: failed to query sample data\n");
 			return B_ERROR;
 		}
+
+		if (cookie->samples[1] == 0x74 && cookie->version == 3) {
+			TRACE("ELANTECH: absolute mode broken, forcing standard PS/2 protocol\n");
+			return B_ERROR;
+		}
 	}

 	if (enable_absolute_mode(cookie) != B_OK) {