Message-ID: <20091216172445.GA6800@core.coreip.homeip.net>
Date:	Wed, 16 Dec 2009 09:24:45 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	Alex Chiang <achiang@...com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-input@...r.kernel.org
Subject: Re: synaptics touchpad doesn't click

On Wed, Dec 16, 2009 at 10:17:39AM +0100, Takashi Iwai wrote:
> At Wed, 16 Dec 2009 00:23:16 -0800,
> Dmitry Torokhov wrote:
> > 
> > On Wed, Dec 16, 2009 at 08:14:15AM +0100, Takashi Iwai wrote:
> > > At Tue, 15 Dec 2009 22:56:53 -0800,
> > > Dmitry Torokhov wrote:
> > > > 
> > > > On Wed, Dec 16, 2009 at 07:50:54AM +0100, Takashi Iwai wrote:
> > > > > At Tue, 15 Dec 2009 18:59:34 -0800,
> > > > > Dmitry Torokhov wrote:
> > > > > > 
> > > > > > On Tue, Dec 15, 2009 at 06:05:06PM -0700, Alex Chiang wrote:
> > > > > > > * Dmitry Torokhov <dmitry.torokhov@...il.com>:
> > > > > > > >
> > > > > > > > The updated patch is below.
> > > > > > > > 
> > > > > > > > -- 
> > > > > > > > Dmitry
> > > > > > > 
> > > > > > > Should I test this one or wait one more iteration to address
> > > > > > > Takashi's last comments?
> > > > > > > 
> > > > > > 
> > > > > > Actually I think we took the wrong direction with the original patch and
> > > > > > we should do what other buttonless devices (bcm5974) do: report touchpad
> > > > > > click as left button and have Synaptics X driver provide enhanced
> > > > > > support. This way we can have both modes (ClickZones and ClickButtons)
> > > > > > and users will get to chose (provided that someone takes time to add
> > > > > > that support to Synaptics driver of course ;) ).
> > > > > 
> > > > > My concern is, still, how would you identify this device.  Will you
> > > > > extend also some ioctls to expose caps and extcaps?  Otherwise it's
> > > > > difficult to identify this device automatically from the user-space.
> > > > > 
> > > > 
> > > > No.. Synaptics without right button == ClickPad.
> > > 
> > > So, is there only Clickpad device that has a single button?
> > > No other option?
> > > 
> > 
> > I have not seen any other Synaptics devices using less than 2 buttons.
> > 
> > > > > The user-space can know that it's button-less, yes.  But, how can it
> > > > > know whether the device should be emulated via ClickZone?
> > > > > We can use a driver option to x11 synaptics driver for that, as I
> > > > > already sent you another patch.  However, the driver option is
> > > > > nowadays not preferred because xorg.conf is being dead on new
> > > > > systems...
> > > > 
> > > > Driver still takes options, from UDEV/HAL. We could pick one behavior
> > > > by default and ovverride, by box vendor/model (DMI).
> > > > 
> > > > > 
> > > > > Or maybe HAL (or whatever upcoming one) can check the vendor/product
> > > > > id of the machine (not the device) to provide the information.  OTOH
> > > > > this will also need frequent updates.
> > > > 
> > > > Hopefully vendors won;t be flip/flopping between ClickZone and
> > > > ClickButtons too much. Still option is better than hardcoding ClickZone
> > > > for everyone.
> > > 
> > > Yeah, I agree that hard-coding isn't good, and that's why I first
> > > posted separated patches.  OTOH, the kernel-side hack makes the device
> > > working *as is* even without changing anything else.
> > >
> > 
> > For "ClickZone" - yes, but not all users would want this I guess and not
> > all laptops will have that zone marked. Pushing it off to userspace
> > gives more flexibility, including the ability to change zone size, etc.
> 
> As mentioned, I agree basically for the user-space implementation for
> a long term solution.  My point is that the kernel hack can be
> regarded as a quick hack for a short term while you have no patch yet
> for the user-space driver.  It'll take time until the user-space
> update will be deployed in many distros while people tend to update
> only the kernel.

I strongly disagree here. The fact that some users are more likely to
update kernel than userspace bits is immaterial, besides such users can
easily patch their kernels with out-of-tree patches. Additionally kernel
patch would prevent writing proper userspace support because userspace
will not be able to reconstruct full device state (you are filtering out
some events).

-- 
Dmitry
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