[Bug 133060] Re: Synaptic touchpad fails to register some of the taps for tap-to-click

[Bryce Harrington]

Regarding Nicolas' patch to do edge detection prior to calling
SelectTapButton, to get that in I would suggest posting it to the xorg-
devel mailing list on freedesktop.org for review first.

** Changed in: xserver-xorg-input-synaptics (Ubuntu)
       Status: Confirmed => Fix Committed

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Synaptic touchpad fails to register some of the taps for tap-to-click
https://bugs.launchpad.net/bugs/133060
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Status in “xserver-xorg-input-synaptics” package in Ubuntu: Fix Committed
Status in “xserver-xorg-input-synaptics” package in Debian: New

Bug description:
Binary package hint: xserver-xorg-input-synaptics

When using tap-to-click, the synaptics driver fails to register some taps as clicks. I have managed to link this with abnormal coordinates reported by the driver using "synclient -m 10". Whenever a tap is not registered as a click, there is one or more consecutive reports of touching at coordinates (x=1, y=5855), which might explain why it is not registered as a click.

I have recorded a few taps and saved them as a .txt file, which you can view at: http://ubuntuforums.org/showpost.php?p=3202355&postcount=5

by watching the output of "synclient -m 10" I have been able to find a pattern, when taps are registered and when they're not. I have found that every time a tap is not registered there is a weird "1" appearing on the X column and a "5855" on the Y column, meaning that my touchpad registered touch at the (1,5855) coordinates. This, coupled with the MaxTapMove=220 (default), means that it will register a movement during my tap and as such it will invalidate it as a tap.

[lspci]
00:00.0 Host bridge [0600]: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express Memory Controller Hub [8086:27a0] (rev 03)
     Subsystem: Dell Unknown device [1028:01bd]
01:00.0 VGA compatible controller [0300]: ATI Technologies Inc Radeon Mobility X1400 [1002:7145] (prog-if 00 [VGA])
     Subsystem: Dell Unknown device [1028:2003]