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Re: ts rotation with mt driver, possible utouch interferences


Quoting Chase Douglas <chase.douglas@xxxxxxxxxxxxx>:

On 05/27/2011 07:15 AM, Lukas-David Gorris wrote:
How to rotate the touchscreen when using the multi touch driver ?

Why is xinput rotation broken in natty while it works with the same
touchscreen driver in maverick ?


In Natty we have deprecated the evdev axis manipulation properties. In
its place we are using the more general input coordinate transformation
matrix. This allows for any linear transformation of input coordinates,
so it's much more flexible than the evdev axis manipulation properties.
It's also provided by the server, so the same properties are used for
all input modules, not just evdev.

For more information, see


-- Chase


Thanks so much! I figured out by now - cnd from freenode pointed me towards this - and was just about to update the mailing list :)

Trying out the CTM (Coordinate Transformation Matrix) in nattys xorg, it does not work out of the box. I got a jumpy cursor after rotating. This was due to a bug in the natty release images: See https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/774938 In order to solve this you need to run "apt-get update; apt-get upgrade" The package that was affected by this was xserver-xorg-core . In my case it was sufficient to only upgrade that package.

Conclusion: If you run into unexpected xinput touchscreen rotation problems after upgrading to ubuntu natty do the following:

1) Upgrade your system in order to fix broken Xorg in natty release images.

2) Read https://wiki.ubuntu.com/X/InputCoordinateTransformation because the pointer / xinput rotation mechanism in Xorg has changed.

It's always a pleasure to try out new ubuntu images on mobile devices with all the kind help received!

Best regards