Touchpad Issue in Cinnamon 17.2

[Sandro]

General description:
A problem with my laptop's touchpad in Linux Mint. The touchpad has a dedicated on/off button and works just fine as long as I don't press that button. When I press the button, I get a flickering touchpad icon and a "dancing" touchpad settings menu. The cursor can't be controlled, for it moves in leaps and with huge delays. I've discovered that pressing any key (for instance, Enter) seems to fix the problem but only until I shut down or restart the system. So if I press any key, Linux Mint disables the touchpad, and if I enable it again, it works just fine and can be safely turned on and off using the dedicated button. The issue occurs if the mouse is connected or not.

My YouTube video showcasing the problem:
https://www.youtube.com/watch?v=PMk2CD6A3Eo

Details:
- Laptop: HP Compaq Presario CQ61-315ER
- Distro: Linux Mint 17.2 Cinnamon Edition
- LiveDVD or real installation issue: both
- Installation: fresh, level 1-3 updates, default repos, Broadcom & Nvidia drivers (the issue occurs with default drivers as well)
- Dual-booting: no
- Partition table: MBR
- Partition layout: root, swap, home
- Distros with no such problem: Linux Mint Xfce & MATE Editions (real installation); Linux Lite / LXLE / Simply Linux (LiveDVD)
- Distros with the same problem: Ubuntu 14.04.3 LTS (LiveDVD)

Just-in-case info:
Coincidence or not, the Cinnamon Edition seems to be the only one in which I experience a pretty heavy mouse and keyboard lag. It affects scrolling (the slider may just freeze), the selection of an item on a list (the lag can be so bad that I miss the item I need), text selection (the actual selection lags behind the cursor), typing (letters appear with a delay). The keyboard is lagging even as I type this. The only distro or flavor that works great on this particular laptop is Linux Mint 17.2 MATE Edition. Not a single issue. It doesn't even freeze on restart after a fresh installation, so no need for Alt+PrScr+reisub.