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: Arjan Opmeer <arjan@opmeer.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 6ab0eb1a..d3b5916 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -1,7 +1,7 @@
/*
- * 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 @@
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 @@
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 @@
}
input_sync(dev);
+
+ discard_packet_v1:
+ old_fingers = fingers;
}
/*
@@ -662,6 +674,17 @@
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;