External touchpad for Ubuntu?

[Robert Heller]

At Mon, 21 Dec 2020 00:45:07 +1100 "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> I have a laptop computer, and, as I have explained many times before now,
> it annoys me no end that I cannot disable my touchpad.

On my *Lenovo Thinkpad R500* laptop, it is possible to disable the touchpad at
the *BIOS* level (which I have done -- I use the point-stick instead). I would
go hunting in BIOS settings land to find a possible setting there.

> 
> I have heard people say that I should just plug a mouse in, but I don't
> want to buy myself a mouse just so I can disable my touchpad. But I do
> think that I could buy myself an "external touchpad". I have my laptop on
> my lap, and I think that if I plug in an external touchpad, and rest it on
> the arm of my chair, this setup might just work.
> 
> I did a quick search, and found while these devices do exist, I found only
> a few references where people have wanted to use an external touchpad in
> Ubuntu, and nothing useful about which vendors might sell a reliable
> external touchpad (one that would disable the laptop's touchpad when in use
> and have the same or a similar set of gestures as the internal one) with a
> recent release of Ubuntu. I hope there's something.
>

"Standard" USB HID devices like keyboards, keypads, mice, trackballs, and I
expect external touchpads all follow a standard USB HID protocol -- these
devices just plain work, without needing special devices or configuration,
beyond standard things like keyboard layout or left hand vs right hand mice,
etc. Note: typically these devices are "or"ed -- if you plug in a USB keyboard
into your laptop, both the external and internal keyboard work -- you can
alternitively type on both. Ditto with an external pointer device -- both
work. And this includes multiple built in devices -- if I enabled the touchpad
on my laptop, I could use both the touchpad and the pointstick. There is no
protocol for an external HID device disabling an "internal" HID device. And no
(standard) software API for making a hard selection between HID devices. The
Linux GUI subsystem is perfectly happy to work seamlessly with multiple
keyboards (or keyboard-like devices like barcode readers) and multiple pointer
devices (trackballs, touchpads, mice, pointsticks, touchscreens, etc.) all at
the same time.

On my laptop, the touch pad is separate from the keyboard and has its own
connector on the motherboard. As a last resort, you might be able to just
unplug the touchpad from the motherboard. (But I don't know what possible
problems that might cause -- the BIOS might fail a self-test and refuse to
boot the O/S -- I recall a *brain dead* 1990s vintage Dell server that would
refuse to boot without a keyboard plugged in, even with "Halt on no errors"
set in the BIOS!) 

> Thanks for letting me know,
> 
>   Owen.
> 

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