linux-kernel - Re: Three buttons reported on two-button touchpad

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Date:	Sun, 15 Nov 2009 11:48:29 +0300
From:	Andrey Borzenkov <arvidjaar@...l.ru>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Three buttons reported on two-button touchpad

On Sunday 15 of November 2009 09:20:36 Dmitry Torokhov wrote:
> Hi Andrey,
> 
> On Sat, Nov 14, 2009 at 03:51:10PM +0300, Andrey Borzenkov wrote:
> > Kernel 2.6.31.x
> >
> > dmesg:
> > Synaptics Touchpad, model: 1, fw: 6.3, id: 0x1c0b1, caps:
> > 0xa04751/0x0
> >
> > but /proc/bus/input/devices:
> >
> > I: Bus=0011 Vendor=0002 Product=0007 Version=01b1
> > N: Name="SynPS/2 Synaptics TouchPad"
> > P: Phys=isa0060/serio1/input0
> > S: Sysfs=/devices/platform/i8042/serio1/input/input15
> > U: Uniq=
> > H: Handlers=mouse1 event2
> > B: EV=b
> > B: KEY=420 70000 0 0 0 0
> > B: ABS=11000003
> >
> > So even when capabilities clear say only 2 buttons, driver claims
> > there are 3 of them.
> >
> > The reason most likely is initialization sequence.
> > psmouse_switch_protocol() unconditionally sets supported buttons:
> >
> >         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
> >         input_dev->keybit[BIT_WORD(BTN_MOUSE)] = BIT_MASK(BTN_LEFT)
> > | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT); input_dev->relbit[0]
> > = BIT_MASK(REL_X) | BIT_MASK(REL_Y);
> >
> > before even starting hardware detection and knowing real
> > capabilities. Detection for specific hardware won't change it
> > (possibly only extend).
> 
> Some of them do.
> 
> > Is it OK to move button bits setting into ps2bare_detect()? This
> > seems to agree with comments in psmouse_extensions() as well:
> >
> > /*
> >  * Okay, all failed, we have a standard mouse here. The number of
> > the buttons
> >  * is still a question, though. We assume 3.
> >  */
> >
> > All other detection routines seem to be setting those bits already.
> 
> Not all of them but yes, I think we should to this. DOes th patch
>  below work for you?
> 

Yes (I can test only Synaptics case).

Tested-by: Andrey Borzenkov <arvidjaar@...l.ru>

> +       input_dev->keybit[BIT_WORD(BTN_MOUSE)] =
> +                               BIT_MASK(BTN_LEFT) | 
BIT_MASK(BTN_RIGHT);

Just curious - is Apple touchpad (as found on MacBook) handled by 
different driver? Because it has just single button.

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