Re: syndaemon-netbsd : a program to disable a synaptics-compatible trackpad while typing

[thezerobit <thezerobit%posteo.com@localhost>]

Thanks,

The way I handle the permissions is just to `chown root` and `chmod u+s` 
the binary. I have a line that runs it in daemon mode at the top of my 
~/.xinitrc file for convenience. The sysctl variable name and values it 
can be set to are hard-coded. I could split the sysctl calls into a 
separate binary to minimize attack surface area, making a guess at your 
reference to a "suid helper". Any examples or literature on the topic 
you might know about would be helpful, if there's more to it than just 
that. I'm a programmer, but I generally don't write code that runs as 
root or do much system administration, so my knowledge in the area is 
rudimentary.

Yes, initially I had experimented with disabling the /dev/wsmouse device 
using xinput, but that is buggy, unfortunately. When reenabling the 
device, it causes audio playback to stutter for a moment and it causes 
keyboard input issues, like the return key will start repeating 
endlessly until I hit it again (at least on NetBSD 11 RC3 and RC4). You 
have to `enable` the device 2 times to get things back to a normal 
working state. Obviously, the daemon is going to be disabling/reenabling 
the device constantly, so that's not really workable. I didn't find 
anything in wsconsctl, wsconsio.h or manual pages related to wscons that 
I could use to disable the trackpad. It was in the `pms` man page that I 
found a sysctl variable that would do the trick. Since it is a the 
trackpad level, it only disables trackpads, not mice, which is 
convenient. If people thought this was useful enough to go into NetBSD 
proper, it might be good to have a generic enable/disable switch 
(whether a sysctl variable or something else) for trackpads rather than 
relying on the finger_high trick.

-thezerobit

On 05/26/2026 12:55 am, Aryabhata wrote:
> Hey,
>
> Thanks for sharing this! Dealing with palm-press trackpad jumps on a
> ThinkPad is incredibly annoying, so this is definitely a welcome for
> anyone running NetBSD on a laptop.
>
> The finger_high sysctl trick is a pretty clever workaround to bypass
> the driver interpretation entirely. One quick question on how you're
> handling it: since writing to sysctl knobs usually requires root, does
> the daemon have to run with elevated privileges? Running an X-centric
> tool as root can be a bit sketchy security-wise, so I'm curious if
> you've looked into separating the X11 listener from the actual sysctl
> call, or using a small suid helper.
>
> Also, out of curiosity, did you run into issues trying to use
> user-space tools like xinput or wsconsctl to toggle the device? I know
> if you're using the generic wscons driver it tends to multiplex
> everything into one stream, which makes isolating just the trackpad a
> massive pain—assuming that's why you went the kernel route.
>
> Either way, nice work getting this up.
>
> Cheers,
>
> Aryabhata
>
> On Tue, 26 May, 2026, 3:43 am thezerobit, <thezerobit%posteo.com@localhost>
> wrote:
>
> > Hi,
> > I hacked syndaemon to work on NetBSD. Codeberg page:
> > https://codeberg.org/thezerobit/syndaemon-netbsd [1] . Direct
> > download:
> > https://codeberg.org/thezerobit/syndaemon-netbsd/archive/main.tar.gz
> > [2]
> >
> > If you don't know what syndaemon is, it's a little daemon that pays
> >
> > attention to keyboard activity in X and disables the trackpad while
> > you
> > are typing. This is to prevent unintentional mouse movements and
> > clicks
> > on laptop trackpads located just below the keyboard. This is pretty
> > much
> > essential when working on my Thinkpad T580. There is a README.txt
> > in the
> > repo which explains how to compile and use the tool.
> >
> > The reason this is a bit of a hack is that the only way to safely
> > disable the trackpad that I could find was to set the sysctl
> > variable
> > "hw.synaptics.finger_high" to a high enough value that the driver
> > no
> > longer registers interaction. Feel free to contact me directly with
> >
> > feedback or suggestions on how to improve it or if you need help
> > getting
> > it working.
> >
> > -thezerobit
>
>
> Links:
> ------
> [1] https://codeberg.org/thezerobit/syndaemon-netbsd
> [2] 
> https://codeberg.org/thezerobit/syndaemon-netbsd/archive/main.tar.gz