I upgraded my kernel from 2.4.22 to 2.6.6 on my asus m2400n laptop and everything except the touchpad is working to my satisfaction.

I have the synaptics driver installed and working. Double tapping works, all three buttons work, etc. The only problem is that it is not smooth at all which makes it very frustrating to use. It is even worse in the console! Does anyone know why when using my touchpad the curser position only updates ~1 time per second? Or ~1 time per 3 seconds in the console? and how to fix it?

Observations that may prove helpful:
-When using my external usb mouse the cursor movement is smooth.
-Cursor movement with the touchpad was smooth under the 2.4.22 kernel.
-Installing the synaptics driver made a small improvement to the touchpad performance but it is still frustratingly lagy.

I'm using this updated driver on a 2.6.5 kernel. It seems to work fine.

Good luck!

ps-you can change sensitivity and such in your xfree86 config file

That is exactly the same driver that I am using and I have played with the xf86config settings. It seems as though the sample rate is very low for some reason. I googled looking for sample rate issues and apparently if the 2.6.x kernel doesn't recognise the mouse it sets some crappy defaults for the sample rate. Adding this: psmouse_noext=1 to the kernel parameters in the loader was suggested. But I won't get a chance to try that until after work

Here is the link to where that solution was suggested for anyone who is interested http://kerneltrap.org/node/view/1587 It includes a discussion between Linus Torvalds and Vojtech Pavlik about the problem and possible solutions.

minus the . this is the link: http://kerneltrap.org/node/view/158

Yeah ignore this I forgot about editing posts pity you can't remove posts aswell

you know you can just click the "edit" button to make changes to your posts, right?

Let us know if this fixes your jitters

No, that kernel parameter didn't fix the touchpad jitters. Nor did any other psmouse parameters. When I passed acpi=off as a kernel parameter the touchpad became smooth again. So my best guess is that it is an acpi problem. Can anyone suggest a fix because I want apci on. Also for some reason when apci is off the alsa drivers don't work. Anyone know why?

Ok, the kernel parameter pci=noapci has fixed it but now alsa doesn't work!! Does anyone know why with this kernel parameter alsa doesn't work?

I've finally got everything working for anyone who is interested http://seclists.org/lists/linux-kern.../May/1593.html describes the problem and solution. Passing only acpi_irq_isa=12 to the kernel was the final solution.