Battery drain & processor always at max
Solution 1:
Finally I found the cause, I'll post it in case anyone has the same issue. I googled the exact device that showed in the IRQ, and found that some MSI PS63 users who installed Linux found themselves with the same issue: https://bbs.archlinux.org/viewtopic.php?pid=1862570#p1862570
The problem comes from the touchpad. In my case, rebinding the i2c bus solved the problem:
sudo -i
echo -n "i2c_designware.0" > /sys/bus/platform/drivers/i2c_designware/unbind
echo -n "i2c_designware.0" > /sys/bus/platform/drivers/i2c_designware/bind