multi-touch-dev team mailing list archive

[Ping Cheng <pinglinux@xxxxxxxxx>]

On Wed, Feb 23, 2011 at 9:36 AM, Duncan McGreggor <
duncan.mcgreggor@xxxxxxxxxxxxx> wrote:

>
> -------- Original Message --------
> Subject: Re: touch input rotation
> Date: Tue, 29 Jun 2010 07:43:56 -0700
> From: Kees Cook <kees.cook@xxxxxxxxxxxxx>
> Organization: Canonical
> To: Alberto Milone <alberto.milone@xxxxxxxxxxxxx>
> CC: Federico Mena Quintero <federico@xxxxxxxxxx>,        Bryce
> Harrington <bryce@xxxxxxxxxxxxx>,        Chase Douglas
> <chase.douglas@xxxxxxxxxxxxx>,        "Duncan M. McGreggor"
> <duncan.mcgreggor@xxxxxxxxxxxxx>,        Rick Spencer
> <rick.spencer@xxxxxxxxxxxxx>,        Rafi Rubin <rafi@xxxxxxxxxxxxxx>
>
> Hi Alberto,
>
> On Tue, Jun 29, 2010 at 04:20:56PM +0200, Alberto Milone wrote:
> > On 28 June 2010 20:14, Kees Cook <kees.cook@xxxxxxxxxxxxx> wrote:
> > > I saw your touch input rotation work[1].  I was looking at this too,
> > > and I think it needs to be done more generally (in gnome-desktop rather
> > > than g-s-d), and with XInput (rather than calling out to xsetwacom).
>

I agree with Alberto on this point. Using something generic, like Xinput,
rather than vendor/project-specific helps the community in the long term.

 > > I've got a patch to do it here:
> > >
> > > https://launchpad.net/bugs/599478
> > > http://launchpadlibrarian.net/51043158/101_rotate-touch-devices.patch
>
>
> > According to Rafi (who I'm subscribing) there are cases in which we
> > may not want to auto rotate input devices:
> >
> > "Simply differentiating pen and touch is insufficient.  Most of the
> > wacom touch screens seem to have pen, and we would want to rotate
> > those pens.  We also see devices like the bamboo tablets which
> > identify as touch, but aren't attached to the screen and shouldn't
> > auto rotate. And then there's messes like ntrig devices, where we're
> > moving towards using evdev for touch and the wacom x driver for pen"
>
> I suspected not all "Wacom Tool Type" == "TOUCH" devices would qualify,
> but I wanted to start somewhere.  I suspect it would be better to have
> the devices self-identify as "attached to screen orientation" or not, so
> the code to find them is simpler.  In the meantime, my struct
> GnomeXiDetails could be extended.  I was treating it as a whitelist
> currently.
>

Wacom X driver can tell you if the device is a touchscreen, touchpad, or
tablet. But, as I mentioned above, relying on a specific device/driver would
only support a limited number of devices. A generic way to tell the type of
the device helps all devices.


> > I think that perhaps using either a blacklist or regular expressions
> > to indentify devices would help. This said, I still think that we
> > can't get this right for all devices, therefore I recommend that we
>

The good news is that kernel input subsystem has added (maybe not in the
tree yet, Henrik should be able to tell us more) a new set of ioctl so we
can retrieve the device types directly from the kernel. With this new ioctl,
generic "device self-identification" is available.

 > adopt Federico's approach where a gconf key allows users to disable
> > automatic rotation of input devices. This is not enough but at least
> > it should make things less annoying for users who don't want to rotate
> > inputs. We might as well have a text file with the blacklist so that
> > users can add devices that shouldn't rotate there (this would help
> > OEMs a great deal).
>
> Agreed -- having this under more direct control is a win, though it
> should DTRT by default.
>

I am with both of you here. We need to enable end users with a one button
click to enable or disable automatic rotation of input devices in the UI so
users have choices when they do not want to go with the default setting.

Ping