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diejengent 11-03-2012 06:42 AM

synaptics touchpad problem with doubletap

I am using a synaptics touchpad in my laptop.

It works just fine, but when I want to enable the doubletab function (either via Gconf in Gnome or straight via /etc/X11/xorg.conf) it freezes after a short while. It also freezes my laptop keyboard. I have to plug in a usb keyboard to log out from X and even after that the laptop keyboard is still frozen and I have to reboot.

It's only with the doubletap implementation; otherwise the touchpad works perfectly fine.

Any insights on dealing with this problem?

diejengent 11-03-2012 07:03 AM

I already have to correct myself.

Without the doubletap configuration it also freezes. It just takes much longer.
With the doubletap configuration it freezes within a minute of use.

diejengent 11-30-2012 04:32 AM

hardware problem
I have been testing alot with different settings and drivers.
It turns out it happens both with the synaptics driver and the evdev driver.
So it seems no bug or something but a hardware problem. This is what happens (I use a HP Pavilion laptop)...

At some random point in 30 mins (could be the first minute, could be the last) the entire keyboard and the touchpad freeze up.
The keyboard does not respond at all (when pressing caps lock the led also does not light up!).
Unloading Xorg does not change anything. Only a reboot can revive the keyboard and touchpad.
xinput still lists both input devices as present and active.
Nowhere in any log (both xorg and kernel) is something to be found concerncing this problem.

For now I removed PS/2 support from the kernel. I don't use the touchpad much anyway. For me it is just a hobby to get everything to work under Linux and maybe other people can learn while searching for a solution to a simular problem.

Does anybody have an idea what is going on here?

diejengent 02-01-2013 10:00 AM


The problem also occurs without PS/2 support in the kernel.
Only then it happens very rarely (about once in 2 months of heavily use). The keyboard freezes entirely, also disabling leds like caps lock and num lock.

I found an ugly solution for recovering the keyboard without having to destroy ongoing processes:

1. connect an usb keyboard
2. as root hibernate the system on the swap partition with: "echo disk > /sys/power/state"
3. restart
4. disconnect the usb keyboard again

The system returns in it's last state and the laptop keyboard suddenly works again.

What remains weird is that there is absolutely no reference to this in the kernel log, which makes me think that this is entirely a hardware problem.
Although this freezing of the keyboard never ever happened in Windows.

Anyway, I got an ugly solution now, but it would still be interesting for me and others if there would be some 'clean' solution for this problem.

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