tablet-support in Ubuntu

Timo Aaltonen tjaalton at
Tue Sep 30 08:04:47 UTC 2008


   I'll start a new thread, because the ongoing thread became a bit too 
confusing to follow.

Let's clear one thing first:

   8.10 will not remove support for tablets

now repeat that umpteen times.

There has been too much misinformation floating around lately, and + 
admit that the consequences of input-hotplug could have been informed 
better, but I'll take this opportunity to clarify things that confuse 
people the most.

First of all, things might work differently out-of-the-box, but that 
doesn't mean that input drivers couldn't be configured like before if need 
be. By default, the evdev-driver handles all input devices that HAL is 
aware of and which list input.keys/input.mouse as a capability of the 
device. Evdev might not be the best choice for example touchpads or 
tablets, and that's why there needs to be a driver specific HAL fdi-file 
that makes the device use the correct driver. This is true for synaptics 
touchpads, wacom tablets and (some) joysticks (WIP).

Serial devices (some tablets, touchscreens) are more problematic, since 
HAL doesn't know about them without some trickery (which I'm not an 
expert of). But in those cases you should be able to configure them via 
xorg.conf without too much trouble.

Now the workarounds:

-If you like to disable input-hotplug completely, add 'Option 
"AutoAddDevices" "false"' to the ServerFlags-section. Then you are on your 
own, and get to keep both pieces.

-If you like to just skip i-h for a single device you have, add an fdi 
file to /etc/hal/fdi/policy which matches your device and leaves 
input.x11_driver empty. Then you can configure that device in xorg.conf 
and prosper.

Note that the wacom driver doesn't fully support input-hotplug, since 
currently you need to initialize the driver multiple times to enable 
stylus/pen/foo, and that's not possible to do with HAL. The wacom fdi file 
configures the device as stylus..

Timo Aaltonen
Systems Administrator
IT Services, Helsinki University of Technology
tel. +358-9-4514317, mobile: +358-50-5918781

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