linux-kernel - Re: [PATCH 2/3] Input: synaptics - add multi-finger and semi-mt support

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Date:	Tue, 21 Dec 2010 11:35:41 -0500
From:	Chase Douglas <chase.douglas@...onical.com>
To:	Henrik Rydberg <rydberg@...omail.se>
CC:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Jiri Kosina <jkosina@...e.cz>, Takashi Iwai <tiwai@...e.de>,
	Chris Bagwell <chris@...bagwell.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] Input: synaptics - add multi-finger and semi-mt support

On 12/20/2010 08:39 AM, Henrik Rydberg wrote:
> The Synaptics 2.7 series of touchpads support a mode for reporting two
> sets of X/Y/Pressure data (advanced gesture mode). By default, these
> devices report only single finger data, depriving userspace of the
> nowadays ubiquitous two-finger scroll gesture.
> 
> Enabling advanced gesture mode also enables the multi-finger report,
> although the device does not claim that capability. Up to three
> fingers can be reported this way.
> 
> While two or three fingers are touching, the normal packet is
> prepended by a reduced finger packet of lower resolution. From the two
> packets (which do not represent the actual fingers), the bounding
> rectangle of the individual contacts can be extracted.  This
> information is sufficient to perform scaling gestures and a limited
> form of rotation gesture. The behavior has been coined semi-mt
> capability, and is signaled to userspace via the INPUT_PROP_SEMI_MT
> device property.
> 
> Work to decode the advanced gesture packet: Takashi Iwai.
> Cleanup and testing of the original patch: Chase Douglas.
> Minor cleanup and testing: Chris Bagwell.
> Finalization and semi-mt support: Henrik Rydberg.
> 
> Reported-by: Tobyn Bertram
> Not-yet-signed-off-by: Takashi Iwai <tiwai@...e.de>
> Not-yet-signed-off-by: Chase Douglas <chase.douglas@...onical.com>
> Not-yet-signed-off-by: Chris Bagwell <chris@...bagwell.com>
> Signed-off-by: Henrik Rydberg <rydberg@...omail.se>

You can keep my SOB.

> +static void set_slot(struct input_dev *dev, int slot, bool active, int x, int y)
> +{
> +	input_mt_slot(dev, slot);
> +	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
> +	if (active) {
> +		input_report_abs(dev, ABS_MT_POSITION_X, x);
> +		input_report_abs(dev, ABS_MT_POSITION_Y,
> +				 YMAX_NOMINAL + YMIN_NOMINAL - y);
> +	}
> +}

I take it that you feel MT_TOOL_FINGER should always be set, even if
it's always the same as BTN_TOOL_*? I just want to be sure this is
intended so we document it appropriately.

> @@ -623,6 +686,7 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
>  	int i;
>  
>  	__set_bit(INPUT_PROP_POINTER, dev->propbit);
> +	__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);

Shouldn't this only be set when SYN_CAP_ADV_GESTURE(priv->ext_cap_0c) is
true?

Thanks,

-- Chase
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