I just recently switched from 2.4.29 (or whatever it was that came with the slackware 10.1 disc) to 2.6.11.9. However, the mouse is now really jumpy. Well, it's actually a touch pad, since this is a laptop. I'm running this on kde 3.4.

Any ideas what the problem might be?

Did you enable 'Preemptible Kernel' when configuring your new kernel?

I didn't touch anything called that, so if it was on by default, then yes.

I just looked through 'make menuconfig', and I can't seem to find such an option. The closest I could find was 'Debug preemptible kernel', which was turned on.

Look under the "Processor Type and Features" menu.

Oh, I am not sure how I missed that.

Yes, it is enabled.

Edit: I just configured xorg to also use a regular USB mouse, and that works fine. Though I still would like to fix the problem.

There is a patch you can get for X.Org for a synaptics touchpad that is meant to fix the problem but I haven't been able to get it to work as of yet. (I assume it's a synaptics touchpad, that's what I have with the identical problem. It's too sensitive, even unusable.)

Get the patch here

If you can get it to work please let me know how.

Well, the touchpad on my ECS A901 is detected as a Synaptics touchpad, and my USB mouse behaved exactly like the touchpad, except that every tap on the touchpad is detected as a double-tap.

Note that by "exactly like the touchpad" I mean that both the mouse and the touchpad are jerky; the smallest distance the pointer can move is 2 pixels, and if I reboot from a 2.6.x (where x is 5, 9, 10, 11, 11.8 so I think it should cover all 2.6 kernels) kernel to my trusty old 2.4.30 kernel (well, maybe not so old), the touchpad can't be used to click on something; tapping on it doesn't work.

Since both the mouse and the touchpad doesn't work correctly, is this just a configuration problem?

Yea, this is a big problem on laptops and the 2.6 branch. Like the prick that I am, I let loose on bugzilla to the developer of the touchpad changes within the kernel... I feel bad about it, but if it aint broke, don't fix it.... One of my other gripes was that tapping was disabled as well. Touchpads went from working great on 2.4 to being total crap on 2.6.... It seems tapping is enabled in the kernel again (possiblly 'legacy psaux' or some such thing) but it's still jerky as you mentioned.

I've tried the synaptics driver but I don't like it at all. Too hard to configure and it still seemed to be screwy. There is supposed to be a kernel option you can append to your bootloader that reverts to the "old and outdated" way of handling, but I've never been able to get that to work. The only thing that I found to do, is (within Gnome mouse prefrences) to lower the sensitivity of the mouse... I'm sure there is a way to do it in KDE as well, but what if you use fluxbox or some other WM?

Yet another of MANY reasons why I hate 2.6.xx... </rant>

edit /etc/rc.d/rc.gpm
add a -r option to the start line
-r is responsiveness
I use -r 34
high number is faster mouse
lower number is slower mouse

I must say that with the new synaptics X patch and the ksynaptics program for KDE my touchpad is now working perfectly.

synaptics patch
Q/Ksynaptics