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

Commit 3f8c0df4 authored by Arjan Opmeer's avatar Arjan Opmeer Committed by Dmitry Torokhov
Browse files

Input: elantech - provide a workaround for jumpy cursor on firmware 2.34 



It seems that Elantech touchpad firmware version 2.34 on the Hercules eCAFÉ
suffers from a problem where bogus coordinates get reported at the beginning
of a touch action. This causes the mouse cursor or the scrolled page to
jump.

Included patch provides a workaround that discards mouse packets that are
likely to contain bogus coordinates. The workaround is activated when we
detect touchpad with fimware version 2.34.

Signed-off-by: default avatarArjan Opmeer <arjan@opmeer.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 3deb649e

drivers/input/mouse/elantech.c

+25 −2
Original line number Diff line number Diff line 
/*

 * Elantech Touchpad driver (v5)

 * Elantech Touchpad driver (v6)

 *

 * Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net>

 * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published
@@ -178,6 +178,7 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse) 
	struct elantech_data *etd = psmouse->private;

	unsigned char *packet = psmouse->packet;

	int fingers;

	static int old_fingers;



	if (etd->fw_version_maj == 0x01) {

		/* byte 0:  D   U  p1  p2   1  p3   R   L
@@ -190,6 +191,14 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse) 
		fingers = (packet[0] & 0xc0) >> 6;

	}



	if (etd->jumpy_cursor) {

		/* Discard packets that are likely to have bogus coordinates */

		if (fingers > old_fingers) {

			elantech_debug("elantech.c: discarding packet\n");

			goto discard_packet_v1;

		}

	}



	input_report_key(dev, BTN_TOUCH, fingers != 0);



	/* byte 2: x7  x6  x5  x4  x3  x2  x1  x0
@@ -216,6 +225,9 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse) 
	}



	input_sync(dev);



 discard_packet_v1:

	old_fingers = fingers;

}



/*
@@ -662,6 +674,17 @@ int elantech_init(struct psmouse *psmouse) 
		param[0], param[1], param[2]);

	etd->capabilities = param[0];



	/*

	 * This firmware seems to suffer from misreporting coordinates when

	 * a touch action starts causing the mouse cursor or scrolled page

	 * to jump. Enable a workaround.

	 */

	if (etd->fw_version_maj == 0x02 && etd->fw_version_min == 0x22) {

		pr_info("elantech.c: firmware version 2.34 detected, "

			"enabling jumpy cursor workaround\n");

		etd->jumpy_cursor = 1;

	}



	if (elantech_set_absolute_mode(psmouse)) {

		pr_err("elantech.c: failed to put touchpad into absolute mode.\n");

		goto init_fail;

drivers/input/mouse/elantech.h

+3 −2
Original line number Diff line number Diff line 
/*

 * Elantech Touchpad driver (v5)

 * Elantech Touchpad driver (v6)

 *

 * Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net>

 * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published
@@ -104,6 +104,7 @@ struct elantech_data { 
	unsigned char fw_version_min;

	unsigned char hw_version;

	unsigned char paritycheck;

	unsigned char jumpy_cursor;

	unsigned char parity[256];

};