linux-kernel - Re: [PATCH 3/4] Input - synaptics: remove TOPBUTTONPAD property for Lenovos 2015

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Date:	Mon, 2 Feb 2015 13:59:56 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:	Hans de Goede <hdegoede@...hat.com>,
	Peter Hutterer <peter.hutterer@...-t.net>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] Input - synaptics: remove TOPBUTTONPAD property for
 Lenovos 2015

On Wed, Jan 28, 2015 at 03:10:06PM -0500, Benjamin Tissoires wrote:
> The 2015 series of the Lenovo thinkpads added back the hardware buttons
> on top of the touchpad for the trackstick.
> 
> Unfortunately, they are wired to the touchpad, and not the trackstick.
> Thus, they are seen as extra buttons from the kernel point of view.
> 
> This leads to a problem in user space because extra buttons on synaptics
> devices used to be used as scroll up/down buttons. So in the end, the
> experience for the user is scroll events for buttons left and right
> when using the trackstick. Yay!
> Still, this user space problem will be fixed in the user space, and
> the kernel will only handle the TOPBUTTONPAD property - which was not
> a good idea to introduce in the kernel in the first place, I concede.
> 
> Furthermore, Lenovo kept using the PNPIDs that are supposed to be
> "5 buttons" touchpads, so the new laptops also have the
> INPUT_PROP_TOPBUTTONPAD. Yay again!
> 
> Insteead of manually removing each of the new ones, or hoping that we
> know all the current ones, we can consider that the PNPIDs list that
> were given contains touchpads that have the trackstick buttons, either
> physically wired to them, or emulated with the top software button
> property.
> 
> Thanks to the extra buttons capability, we can reliably detect the
> physical buttons from the software ones, and so we can remove the
> TOPBUTTONPAD property even if it was declared as such.
> 
> Cc: stable@...r.kernel.org
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
>  drivers/input/mouse/synaptics.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index d58863b..4f05c9f 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -1129,7 +1129,8 @@ static void set_input_params(struct psmouse *psmouse,
>  
>  	if (SYN_CAP_CLICKPAD(priv->ext_cap_0c)) {
>  		__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
> -		if (psmouse_matches_pnp_id(psmouse, topbuttonpad_pnp_ids))
> +		if (psmouse_matches_pnp_id(psmouse, topbuttonpad_pnp_ids) &&
> +		    !test_bit(BTN_0, dev->keybit))

I do not really like this kind of heuristic, but all
topbuttonpad_pnp_ids are currently Lenovos so I guess it's OK and I'll
apply the patch.

Regarding the tracksick/touchpad buttons I would not mind if we'd mix
them in into pass-through port data - kernel's task is to make sense of
hardware for userspace and in this case raw picture does not seem to
make much sense...

Thanks.

>  			__set_bit(INPUT_PROP_TOPBUTTONPAD, dev->propbit);
>  		/* Clickpads report only left button */
>  		__clear_bit(BTN_RIGHT, dev->keybit);
> -- 
> 2.1.0
> 

-- 
Dmitry
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