Re: [PATCH 1/1] Enable xy scrolling for Apple Magic Mouse

From: Ed Tomlinson <edt@aei.ca>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Michael Poole <mdpoole@troilus.org>,
	Jiri Kosina <jkosina@suse.cz>,
	linux-input@vger.kernel.org,
	Marcel Holtmann <marcel@holtmann.org>,
	linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] Enable xy scrolling for Apple Magic Mouse
Date: Mon, 15 Feb 2010 07:50:25 -0500	[thread overview]
Message-ID: <201002150750.26142.edt@aei.ca> (raw)
In-Reply-To: <20100215071850.GB9135@core.coreip.homeip.net>

On Monday 15 February 2010 02:18:50 Dmitry Torokhov wrote:
> On Sun, Feb 14, 2010 at 06:58:26PM -0500, Ed Tomlinson wrote:
> > On Sunday 14 February 2010 17:51:15 Michael Poole wrote:
> > > Ed Tomlinson writes:
> > > 
> > > > Hi,
> > > >
> > > > Here is a patch that enables xy scrolling with the magic mouse.  I have also
> > > > changed the accelleration logic to work better with xy scrolling.
> > > 
> > > Hi Ed,
> > > 
> > > Your other patch to call input_unregister_device() looks good -- thanks!
> > 
> > Thanks.  One question about it though.  Do we have to check if msc is null before
> > the unregister?
> 
> If it is NULL whan remove() is running there are much bigger problems
> with the driver/HID subsystem.
> 
> > 
> > > I've never used a horizontal scroll wheel -- what are the common uses
> > > for it?  Why should the acceleration be separate for the two directions
> > > rather than using the same factor?  Why does the kernel need to emulate
> > > this rather than having user-space implement the emulation?
> > 
> > Its usefull for scrolling left and right while browsing.  If you use kde it can
> > be used to scroll between applications on the taskbar.   Here most applications
> > with a horizontial scrollbar work as expected.
> > 
> > I first tried with a single acceleration value for both axies.  It leads to confusing
> > things happening.   For example.  I quickly scroll down, then nudge the
> > window to the left.  This works as expect with two values.  With one the
> > nudge is accelerated and moves too far.
> > 
> > My personal goal is to have the basic, apple defined, gestures working
> > from kernel space.  This way the device works as expected without needing
> > to fiddle with X or other managers (think wayland and/or chromeOS).
> 
> I am not sure if this is the desired approach. The current idea is to
> export useable but minimally processed events to userspace and let them
> be turned into gestures there (by evdev, synaptics driver and so forth).

I would go along with this if the code to add the emulation in kernel was large or complex.  
Its not.  About 30 more lines should add the pgup/pgdn code.  

Thanks
Ed