Default [P] Lock/Touchscreen problems

Hi Guys,
i have a problem with my touch/lockscreen. If my device is locked and i wake it up with the power button, i can't unlock it. I take the Ring and want to pull it up but it just wobble a short time. I cant pull it. The same with MIUI ROM (Used VirtousRom ago). I installed MIUI Rom and after this, the tiamat kernel, but no solution.
Sometime it works, sometime it doen't. I have to lock the screen and unlock lock the screen and unlock again. After some tries, it works. Don't know this really annoying problem.

Is it a hardware- or a softwareissue? anybody know this problem?