Does wayland support touch-screen rotation?

[Peter Hutterer]

On Mon, Jun 20, 2016 at 12:25:55PM +0000, Ruei, Eric wrote:
> To whom it may concern:
> 
> I am not sure this is the right place to post Wayland/Weston questions or
> report problems. If it is not, please forgive me and point me to the
> appropriate site.
> Here is the problem that we face:
> The touchscreen on TI AM335x EVM is in reverse order, i.e starting from
> bottom-right instead of top-left.  We were able to handle this at our QT5
> Matrix-Gui application by setting the environment variable
> QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS="rotate=180" with QPA = EGLFS and
> LINUXFB.
> However, this solution is no longer valid when we enable Wayland support
> on AM335x because the touch-screen rotation needs to be handled by the
> Wayland compositor. It seems to us that Weston 1.9 does not support this
> kind of operation after a lot of Web searches.
> 
> My question is whether Wayland compositor should support touch screen
> rotation and if the answer is yes, when will this feature be available?
> Attached please find a hacking patch as a proof of concept only for your
> reference.
> 
> Any inputs and help will be highly appreciated!

if this is device-specific and the device can be detected by userspace the
best solution would be to add a hwdb quirk to libinput to automatically set
the rotation on this screen. This way anyone using libinput gets the right
orientation by default.

Cheers,
   Peter