Re: [Linuxwacom-discuss] Strange Behaviour from xsetwacom

[Jason G. <kil...@gm...>]

On Wed, Mar 14, 2012 at 9:20 AM, T Hall <tah...@gm...> wrote:
> For a while I have been noticing some very strange behaviour from
> xsetwacom.
>
> My system:
> Archlinux
> xf86-input-wacom version 0.14 from official arch repos
> Wacom Intuos3 6x8
>
> I have a script to set up my tablet using various calls to xsetwacom
> (attached: tablet_setup.sh). After running the script once, often the
> wrong key combination is mapped to StripLeftUp (It will output x
> instead of f). In this case, running the script a second time will
> usually result in the correct mapping.
>
> However, even when the script has mapped the Left Strip Up to the
> correct key output, xsetwacom --get on the pad device shows different
> values (See attached file: xsetwacom-get-output). All the Buttons are
> Touch Strip options are wrong except StripRightDown. e.g. I move my
> finger up the left touch strip, it outputs "f", but xsetwacom --get
> claims it's mapped to "key +x -x "
>
> At first, I thought this only seemed to happen when xsetwacom --set is
> called from within a script. The reason for this is that it seems to be
> a case of one call to xsetwacom overwriting what was mapped by a
> previous call, hence a single call to xsetwacom won't produce the bug.
>
> For example, to produce the bug in the terminal:
> $ xsetwacom --set "Wacom Intuos3 6x8 pad" "StripLeftUp" "key +g -g"
> $ xsetwacom --get "Wacom Intuos3 6x8 pad" "StripLeftUp"
> key +g -g
> $ xsetwacom --set "Wacom Intuos3 6x8 pad" "Button" "1" "key +x -x"
> $ xsetwacom --get "Wacom Intuos3 6x8 pad" "StripLeftUp"
> key +x -x
>
> Following this, using the left strip up outputs "g".
>
> It appears that StripLeftUp is set correctly, but then setting Button 1
> interferes with it in a very strange manner, changing the value that
> xsetwacom *thinks* it is set to, and sometimes (see the issue
> mentioned above when the script is run once only) but not always
> changing the value it *is* set to.
>
> If the order of the xsetwacom --set commands is reversed, so that
> "Button 1" is set first, followed by "StripLeftUp", then "Button 1"'s
> mapping gets overwritten by "StripLeftUp"'s.
>
> Note that while the strip functions do have button numbers, 1 is not
> StripLeftUp, it is the top right button on the left hand side. (IIRC,
> the 4 touch strip functions are Buttons 4,5,6,7)
>
> Apologies for the length of this email; it's a very odd and slightly
> unpredictable behaviour, so I wanted to make sure I described as fully
> as possible.
>
> Regards
> T Hall

Looks like the cause is xsetwacom re-using action atoms when it
shouldn't. When creating the name for an action atom, xsetwacom takes
the standard prefix "Wacom button action" and appends a number
corresponding to the array index the atom will be stored at. Both
button 1 and StripLeftUp are stored in array index 1 of different
properties, and wind up having the same action atom name. When setting
either button 1 or StripLeftUp, we modify the "Wacom button 1"
property, which winds up changing the action to be performed for
both...

I'll whip up a patch that should fix this shortly...

Jason

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