XInput: Atmel maXTouch Digitizer touch screen

[Chase Douglas]

On 12/21/2011 02:52 PM, Ben Bucksch wrote:
> I have unsuccessfully tried the whole day to configure the "Atmel 
> maXTouch Digitizer" with USB ID 03eb:211c . This is a touch screen and 
> does appear in X.org as input device. It is working rudimentary, but bad 
> enough to be unusable.
> 
> The machine is a Samsung "Series 7 Slate" XE700T1A, a tablet with 
> standard notebook hardware.
> I am using Ubuntu 11.10 with Ubuntu kernel 3.0.0-14-generic and 
> xorg-server 1.10.4-1ubuntu4.2.
> 
> Problems:
> 
> 
> 1. ABSOLUTE
> By default, it's configured in Mode RELATIVE, but it's ABSOLUTE.
> When I do
> xinput --set-mode "Atmel Atmel maXTouch Digitizer" ABSOLUTE
> it works.
> But I need it at the login screen already.
> 
> I do not understand how to just change certain config options about an 
> input device without changing the whole config.
> When I put in /etc/X11/x.org.conf.d/atmel.conf :
> 
> Section "InputClass"
>    Identifier  "Atmel touchscreen"
>    MatchProduct "Atmel Atmel maXTouch Digitizer"
>    MatchIsTouchpad "on"
>    Option "Mode" "Absolute"
> EndSection
> 
> then I get a complaint in the X.org log that the Driver is missing (yes, 
> I shouldn't get that and I don't understand why I do). If I use Driver 
> "synaptics", X.org log complains that it's not a synaptics device. If I 
> use Driver "evdev", the clicking (mouse button, tapping) doesn't at all 
> work anymore.
> 
> Either way, this should work OOTB. Can somebody please fix the driver to 
> make it know that this device is ABSOLUTE?
> 
> 
> 2. Button not released
> 
> Sometimes, it generates only "button 1 pressed", but not "button 1 
> released".
> 
> Strangely enough, this seems to happen only in "onboard" (the Ubuntu 
> onscreen keyboard), but apparently not elsewhere. (I have no idea why.) 
> Unfortunately, that makes my tablet completely useless, because the 
> virtual keyboard then repeats the key endlessly and I can't type a 
> single word. With xinput --test <deviceid>, verified that the "button 
> released" event is (often) missing, when I use the onscreen keyboard.
> 
> I think this also is just a matter of a config tweak, but I haven't 
> found which one.
> 
> Any help appreciated. I feel like I am this close to the dream on a 
> Linux tablet, just some config tweaks, but too far to actually use it.

It actually sounds like you have a hardware driver that does not conform
to the evdev specifications. This is quite common with drivers that ship
with android devices. They work well enough for android, but not for X,
and the driver developers never notice any issues.

A capture of the evdev events would be necessary to debug the issue. You
can use evtest to do this. It needs to conform to what is stated at:

http://git.kernel.org/?p=linux/kernel/git/dtor/input.git;a=blob;f=Documentation/input/event-codes.txt;

That's for basic single touch support. If you want multitouch to work,
the driver will also need to conform to:

http://git.kernel.org/?p=linux/kernel/git/dtor/input.git;a=blob;f=Documentation/input/multi-touch-protocol.txt

-- Chase