[JAUNTY SRU] lp#399787 UBUNTU: The kernel shoud set BTN_TOOL_DOUBLETAP and BTN_TOOL_TRIPLETAP only if the touchpad supports them

[Alberto Milone]

SRU JUSTIFICATION

IMPACT: The kernel in Jaunty reports multi-tap events without checking whether 
they are supported by the device. As a consequence, the X.org driver reports 
that multi-taps are supported in any case. This prevents us from 
distinguishing between (and therefore from fixing) problems affecting 
touchpads which support multi-taps and the ones which don't.

Furthermore applications (under development for OEM) which rely on the ability 
to detect such capability will fail.

We need this for the Dell Mini 10v and for other netbooks affected by the same 
problem.

FIX: commit e42b6646a8298fe06a33a0f68dab661335f5db6e in Linus' branch 
(available since 2.6.29) makes sure that BTN_TOOL_DOUBLETAP and 
BTN_TOOL_TRIPLETAP are set only if the device actually supports them.

TEST: the quickest way to test this is to install Karmic's X.org Synaptics 
driver in Jaunty, restart X, type "xinput list-props $YOUR_TOUCHPAD_NAME" and 
check that "Synaptics Capabilities" reports 1, 1, 1, 0, 0 (the last two 
integers refer to the availability of double-taps and triple-taps 
respectively) on the Dell Mini 10v. Without the fix it reports 1, 1, 1, 1, 1.


BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/399787

Regards,

-- 
Alberto Milone
Sustaining Engineer (system)
Foundations Team
Canonical OEM Services
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