Keyboard and Mouse won't work at the same time

[earlboy]

After a long time, moving from one distro to another I've decided to come back to gentoo.

My problem is when I boot, with both keyboard ang mouse connected, both of them does not work.
If only keyboard is connected during boot, it works. Haven't tried mouse alone since slim doesn't seem to require mouse input.

In XFCE, if both are connected then niether works, if I unplug both then just plug in one it, then that plugged input device works (either mouse of keyboard).

To clarify (in XFCE) :
1. Both keyboard and mouse plugged in. Both does not works.
2. Unplug both, then plug both, nothing works.
3. Unplug both, then plug in keyboard, keyboard works.
4. Unplug both, then plug in mouse, mouse works.

In my xorg log, if I plug in my mouse, it gets configured fine, but I'm getting a message that it's also being configured as a keyboard. Then If I plug my keyboard, it gets detected and configured also as a mouse and keyboard, but during keyboard configuration an error occurs saying "Unable to open evdev device /dev/input/event5" when xorg tries to check the keyboard event.

Mouse : Roccat Cone (buttons can be assigned keystrokes, if programed and does not need any drivers after programming)
Keyboard : A4Tech X7 ( same thing, keys can be assigned as mouse clicks, if programed and does not need any drivers after it is programed)

After further investigation, booting in text mode, keyboard does not work, unplug both then plug both back again, keyboard works. Done a startx and both are working.
Checing Xorg log, I'm still getting "Unable to open evdev device", but this time the keyboard mouse funtion is getting the error thus my mouse works.

If I can fix the "Unable to open evdev device", I think it should work. But I don't know what to do, since the /dev/input/event that cannot be opened changes.

Any advice is much appreciated.

[earlboy]

Update:

Got lucky with whatever xorg is doing. Now my xorg log is showing the error message "Unable to open evdev device" on the mouse side of my A4Tech keyboard, and same error on the keyboard side of my Roccat mouse.
Problem is still there but at least my mouse and keyboard now works.

Still don't know what's causing that error message though.