Re: [PATCH 1/4] Input - synaptics: fix middle button on Lenovo 2015 products

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Jan 28, 2015 at 03:10:04PM -0500, Benjamin Tissoires wrote:
> On the X1 Carbon 3rd gen (with a 2015 broadwell cpu), the physical middle
> button of the trackstick (attached to the touchpad serio device, of course)
> seems to get lost.
> 
> Actually, the touchpads reports 3 extra buttons, which falls in the switch
> below to the '2' case. Let's handle the case of odd numbers also, so that
> the middle button finds its way back.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
>  drivers/input/mouse/synaptics.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index f89de89..0d12664 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -689,7 +689,7 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
>  
>  		if (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) &&
>  		    ((buf[0] ^ buf[3]) & 0x02)) {
> -			switch (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) & ~0x01) {
> +			switch (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap)) {
>  			default:
>  				/*
>  				 * if nExtBtn is greater than 8 it should be
> @@ -698,15 +698,19 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
>  				break;
>  			case 8:
>  				hw->ext_buttons |= ((buf[5] & 0x08)) ? 0x80 : 0;
> +			case 7:
>  				hw->ext_buttons |= ((buf[4] & 0x08)) ? 0x40 : 0;
>  			case 6:
>  				hw->ext_buttons |= ((buf[5] & 0x04)) ? 0x20 : 0;
> +			case 5:
>  				hw->ext_buttons |= ((buf[4] & 0x04)) ? 0x10 : 0;
>  			case 4:
>  				hw->ext_buttons |= ((buf[5] & 0x02)) ? 0x08 : 0;
> +			case 3:
>  				hw->ext_buttons |= ((buf[4] & 0x02)) ? 0x04 : 0;
>  			case 2:
>  				hw->ext_buttons |= ((buf[5] & 0x01)) ? 0x02 : 0;
> +			case 1:
>  				hw->ext_buttons |= ((buf[4] & 0x01)) ? 0x01 : 0;
>  			}
>  		}

Hmm, that switch has gotten unwieldy. Maybe we can do someting like
this:

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index a039cb7..1250a5d 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -608,6 +608,18 @@ static void synaptics_parse_agm(const unsigned char buf[],
 	}
 }
 
+static void synaptics_parse_ext_buttons(const unsigned char buf[],
+					struct synaptics_data *priv,
+					struct synaptics_hw_state *hw)
+{
+	unsigned int ext_bits =
+		(SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) + 1) >> 1;
+	unsigned int ext_mask = GENMASK(ext_bits - 1, 0);
+
+	hw->ext_buttons = buf[4] & ext_mask;
+	hw->ext_buttons |= (buf[4] & ext_mask) << ext_bits;
+}
+
 static int synaptics_parse_hw_state(const unsigned char buf[],
 				    struct synaptics_data *priv,
 				    struct synaptics_hw_state *hw)
@@ -692,28 +704,9 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
 			hw->down = ((buf[0] ^ buf[3]) & 0x02) ? 1 : 0;
 		}
 
-		if (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) &&
+		if (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) > 0 &&
 		    ((buf[0] ^ buf[3]) & 0x02)) {
-			switch (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) & ~0x01) {
-			default:
-				/*
-				 * if nExtBtn is greater than 8 it should be
-				 * considered invalid and treated as 0
-				 */
-				break;
-			case 8:
-				hw->ext_buttons |= ((buf[5] & 0x08)) ? 0x80 : 0;
-				hw->ext_buttons |= ((buf[4] & 0x08)) ? 0x40 : 0;
-			case 6:
-				hw->ext_buttons |= ((buf[5] & 0x04)) ? 0x20 : 0;
-				hw->ext_buttons |= ((buf[4] & 0x04)) ? 0x10 : 0;
-			case 4:
-				hw->ext_buttons |= ((buf[5] & 0x02)) ? 0x08 : 0;
-				hw->ext_buttons |= ((buf[4] & 0x02)) ? 0x04 : 0;
-			case 2:
-				hw->ext_buttons |= ((buf[5] & 0x01)) ? 0x02 : 0;
-				hw->ext_buttons |= ((buf[4] & 0x01)) ? 0x01 : 0;
-			}
+			synaptics_parse_ext_buttons(buf, priv, hw);
 		}
 	} else {
 		hw->x = (((buf[1] & 0x1f) << 8) | buf[2]);
@@ -780,6 +773,7 @@ static void synaptics_report_buttons(struct psmouse *psmouse,
 {
 	struct input_dev *dev = psmouse->dev;
 	struct synaptics_data *priv = psmouse->private;
+	int ext_bits = (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) + 1) >> 1;
 	int i;
 
 	input_report_key(dev, BTN_LEFT, hw->left);
@@ -793,8 +787,12 @@ static void synaptics_report_buttons(struct psmouse *psmouse,
 		input_report_key(dev, BTN_BACK, hw->down);
 	}
 
-	for (i = 0; i < SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap); i++)
-		input_report_key(dev, BTN_0 + i, hw->ext_buttons & (1 << i));
+	for (i = 0; i < ext_bits; i++) {
+		input_report_key(dev, BTN_0 + 2 * i,
+				 hw->ext_buttons & (1 << i));
+		input_report_key(dev, BTN_1 + 2 * i,
+				 hw->ext_buttons & (1 << (i + ext_bits)));
+	}
 }
 
 static void synaptics_report_mt_data(struct psmouse *psmouse,

Thanks.

-- 
Dmitry