Re: [PATCH 0/3] Input: synaptics - multitouch and multifinger support

[Takashi Iwai <tiwai@suse.de>]

At Fri, 08 Oct 2010 18:38:38 +0200,
Takashi Iwai wrote:
> 
> At Fri, 08 Oct 2010 18:37:22 +0200,
> Takashi Iwai wrote:
> > 
> > At Fri,  8 Oct 2010 10:57:57 -0400,
> > Chase Douglas wrote:
> > > 
> > > Tobyn Bertram reverse engineered the multitouch protocol for Synaptics devices.
> > > I've been able to take his work and produce a series of commits to enable MT
> > > and multifinger (MF) support.
> > > 
> > > Unfortunately, there's a tricky issue with some Synaptics touchpads that have
> > > integrated buttons. For example, the left and right buttons on the touchpad of
> > > my Dell Mini 1012 consist of the lower ~20% of the touchpad surface. The
> > > touchpad physically clicks under these areas.
> > > 
> > > The X synaptics input module now has a parameter to disable touches occuring
> > > over the button area, but this solution still doesn't work perfectly. If you
> > > click a button and drag with another finger near the clicking finger, the
> > > touchpad gets confused.
> > > 
> > > Now that we have full MT support, we can try to handle this scenario better.
> > > What I've found to work best is to make touches vanish if they occur over the
> > > button area of the trackpad while any button is held. This works in conjunction
> > > with the X synaptics driver to disable single touch control over the button
> > > area. With full MT support, the touchpad doesn't seem to get confused when a
> > > click and drag occurs with two fingers close to each other, and it enables MT
> > > gestures and MF support across the entire trackpad when no buttons are held.
> > > 
> > > The first question is whether this seems appropriate to others, or if some
> > > other method would work better. Secondarily, should the solution occur in the
> > > kernel, like I have in the third patch of this series, or should it occur in
> > > the X input module? Although we don't have this information today, we may be
> > > able to query the touchpad in the future to know the area of the integrated
> > > buttons. If that were possible, would the recommended location for the hack
> > > change?
> > 
> > Great!  Finally someone found it out!
> > I found this and made a series of patches in 4 months ago.  Since
> > then, Novell legal prohibited me to send the patches to the upstream
> > due to "possible patent infringing".  Now you cracked out.  Yay.
> > 
> > FWIW, my corresponding patch is below.  It really looks similar in the
> > end ;)  I added a kconfig just to be safer.
> > 
> > Regarding the "clickpad" support: in my case, I implemented almost
> > everything about it in xorg driver.  I'm going to submit xorg
> > patches.
> 
> BTW, yet another kernel patch is missing; the support of embedded LED.
> I've posted this once, but it seems forgotten since then.  Reposted
> below.

Oh, any yet another patch, which enables multi-touch mode forcibly.
I see a similar option in your patch, so this might be useless.

But, I found that some old laptops have a little MT-support although
they have no such capability bit.  They can detect multi-fingers but
can't track the positions, it seems.  We'd need to add some whitelist
for such devices.


Takashi

---
From: Takashi Iwai <tiwai@suse.de>
Subject: Add multi_touch parameter to psmouse driver

The multi-touch feature of Synaptics device is disabled unless this option
is set.  Setting to 2 forces the multi-touch mode no matter whether the
feature is detected or not.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/input/mouse/synaptics.c |  106 +++++++++++++++++++++++++++++++---------
 1 file changed, 83 insertions(+), 23 deletions(-)

--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -482,10 +482,88 @@
 }
 
 #ifdef CONFIG_MOUSE_PS2_SYNAPTICS_MULTI_TOUCH
-#define is_multi_touch(priv)	(priv)->can_multi_touch
+static int multi_touch_flag;
+
+static void setup_multi_touch(struct psmouse *psmouse, int verbose);
+
+static struct psmouse *_psmouse;
+
+static int param_set_multi_touch(const char *val, const struct kernel_param *kp)
+{
+	int mode, mode_changed;
+
+	if (!val)
+		return -EINVAL;
+	mode = simple_strtol(val, NULL, 0);
+	if (mode < 0 || mode > 2)
+		return -EINVAL;
+	mode_changed = mode != multi_touch_flag;
+	multi_touch_flag = mode;
+	if (mode_changed)
+		setup_multi_touch(_psmouse, 1);
+	return 0;
+}
+
+#define param_check_multi_touch(name, p) __param_check(name, p, int)
+
+static struct kernel_param_ops param_ops_multi_touch = {
+	.set = param_set_multi_touch,
+	.get = param_get_int,
+};
+
+module_param_named(multi_touch, multi_touch_flag, multi_touch, 0644);
+
+static inline int is_multi_touch(struct synaptics_data *priv)
+{
+	return (multi_touch_flag == 2 ||
+		(priv->can_multi_touch && multi_touch_flag));
+}
+
+static void setup_multi_touch(struct psmouse *psmouse, int verbose)
+{
+	struct input_dev *dev;
+	struct synaptics_data *priv;
+
+	_psmouse = psmouse;
+	if (!psmouse)
+		return;
+	dev = psmouse->dev;
+	priv = psmouse->private;
+	if (!dev || !priv)
+		return;
+	if (is_multi_touch(priv) &&
+	    !synaptics_init_multi_touch(psmouse)) {
+		if (verbose)
+			printk(KERN_INFO "Synaptics: enabling multi-touch\n");
+		if (!SYN_CAP_MULTIFINGER(priv->capabilities)) {
+			__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
+			__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
+		}
+		input_set_abs_params(dev, ABS_MT_POSITION_X,
+				     XMIN_NOMINAL, XMAX_NOMINAL, 0, 0);
+		input_set_abs_params(dev, ABS_MT_POSITION_Y,
+				     YMIN_NOMINAL, YMAX_NOMINAL, 0, 0);
+		input_set_abs_params(dev, ABS_MT_PRESSURE, 0, 255, 0, 0);
+		input_abs_set_res(dev, ABS_MT_POSITION_X, priv->x_res);
+		input_abs_set_res(dev, ABS_MT_POSITION_Y, priv->y_res);
+	} else {
+		if (verbose)
+			printk(KERN_INFO "Synaptics: disabling multi-touch\n");
+		if (!SYN_CAP_MULTIFINGER(priv->capabilities)) {
+			__clear_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
+			__clear_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
+		}
+		__clear_bit(ABS_MT_POSITION_X, dev->absbit);
+		__clear_bit(ABS_MT_POSITION_Y, dev->absbit);
+		__clear_bit(ABS_MT_PRESSURE, dev->absbit);
+	}
+}
+
 #else
 #define is_multi_touch(priv)	0
+#define setup_multi_touch(ps, v) do { } while (0)
 #endif
+
 /* the multi-touch packet contains w=2 (like pen) */
 #define is_multi_touch_packet(priv, hw) \
 	(is_multi_touch(priv) && (hw)->w == 2)
@@ -781,7 +859,7 @@
 	__set_bit(BTN_LEFT, dev->keybit);
 	__set_bit(BTN_RIGHT, dev->keybit);
 
-	if (SYN_CAP_MULTIFINGER(priv->capabilities) || is_multi_touch(priv)) {
+	if (SYN_CAP_MULTIFINGER(priv->capabilities)) {
 		__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
 		__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
 	}
@@ -810,20 +888,11 @@
 		__clear_bit(BTN_RIGHT, dev->keybit);
 		__clear_bit(BTN_MIDDLE, dev->keybit);
 	}
-
-	if (is_multi_touch(priv)) {
-		input_set_abs_params(dev, ABS_MT_POSITION_X,
-				     XMIN_NOMINAL, XMAX_NOMINAL, 0, 0);
-		input_set_abs_params(dev, ABS_MT_POSITION_Y,
-				     YMIN_NOMINAL, YMAX_NOMINAL, 0, 0);
-		input_set_abs_params(dev, ABS_MT_PRESSURE, 0, 255, 0, 0);
-		input_abs_set_res(dev, ABS_MT_POSITION_X, priv->x_res);
-		input_abs_set_res(dev, ABS_MT_POSITION_Y, priv->y_res);
-	}
 }
 
 static void synaptics_disconnect(struct psmouse *psmouse)
 {
+	setup_multi_touch(NULL, 0);
 	synaptics_free_led(psmouse);
 	synaptics_reset(psmouse);
 	kfree(psmouse->private);
@@ -857,8 +926,7 @@
 	}
 
 	synaptics_sync_led(psmouse);
-	if (is_multi_touch(priv))
-		synaptics_init_multi_touch(psmouse);
+	setup_multi_touch(psmouse, 0);
 
 	return 0;
 }
@@ -937,16 +1005,8 @@
 	if (synaptics_init_led(psmouse) < 0)
 		goto init_fail;
 
-	if (priv->can_multi_touch) {
-		if (synaptics_init_multi_touch(psmouse)) {
-			printk(KERN_WARNING "Synaptics: "
-			       "unable to initialize multi-touch\n");
-			priv->can_multi_touch = 0;
-		} else
-			printk(KERN_INFO "Synaptics: multi-touch enabled\n");
-	}
-
 	set_input_params(psmouse->dev, priv);
+	setup_multi_touch(psmouse, 0);
 
 	/*
 	 * Encode touchpad model so that it can be used to set