Sporadic / exaggerated mouse input

[queenkjuul]

I have tried several mice, a very old Logitech USB mouse as well as modern Logitech Unifying mice and a Logitech gaming mouse. When using the PS/2 output to my machine, the mouse is detected, and if I move the mouse very slowly, I can move the cursor accurately, but then without warning any movement sends the mouse fully into the corners, with inputs getting jumbled - mouse clicks will move the cursor up and down or side to side.

When a PS/2 mouse is connected directly to the machine, I have no problems. PS/2 keyboard and 15-pin joystick are working perfectly with this machine. USB4VC is updated to latest firmware, and I've tried both Cutemouse 1.9 and 2.1 with the same results. Mouse sensitivity on the USB4VC is set to 0.25.

I seem to remember getting serial mouse to work with one of these USB mice, but that was over a year ago and I am not currently set up to easily test that. Event code monitor shows normal looking inputs as far as I can tell.

Update: Can confirm that over 9-pin serial, these same USB mice present no issues and I can use them just fine with the Microsoft Serial protocol. Something is going wrong on the PS/2 side. Might try a fresh SD card or something I guess.

[BonzoG]

I have the same issue. PS/2 keyboard is rock solid, but after a few moments of fast movement the mouse will latch to the corners of the screen and cause sporadic clicks whilst jumping around. Unfortunately I don't have a serial interface to test with.

Edit: Managed to find a serial cable, mouse works great that way. Happy to help with logs or testing on the PS/2 side if I can though.

[dekuNukem]

hi there! can you let me know the spec of your PC that has PS/2 issues?

perhaps you can try it on a few different machines and see if it keeps happening?

[BonzoG]

Hi! Thanks for looking at this.

I actually have two very similar machines with totally different behaviour. Both are Intel 440BX chipsets.

#1 Gigabyte GA-BX2000+ Motherboard, Pentium 3 1.1Ghz - PS/2 works flawlessly in W98 & DOS.
#2 Compaq Deskpro (OEM 440BX motherboard with a PC87309 I/O controller), Pentium 2 450MHz - this is the glitchy one, same as OP on this issue. Only DOS installed just now but was the same in Win NT 4.

For now I am happy using serial on the Deskpro :) but curious to know why the glitches are happening. If I can find a PS/2 mouse to test with, I will report back, but so far my issue starts the exact same way as OP. Mouse initially fine, can move it around 'gingerly' and then it just jumps to the corners of the screen, moves rapidly between them, and throws random clicks around.

Cheers

[dekuNukem]

Hmm this usually happens when the PS/2 singal timing is out, very strange it happens on one motherboard but not the other. I'll need to dig out my stash of motherboards and see if I can find one that reproduces this.