I know this thread is quite old, but I believe I found something interesting that I cannot find in previuos posts.
I recently got a second Sensation with a cracked but working digitizer from a colleague and I immediatly noticed the LCD was different to mine. Mine has the AUO display and the other one the SHARP. Color difference and the smoother scrolls are clearly noticeable in the Sharp LCD.
As I liked best how the Sharp looks, I tried to interchange LCDs, keeping the PCB and digitizer of my original phone but using the new LCD. The suprising result is, with this combination of parts, the phone looks like a Sharp one (cold color temperature) but feels like an AUO one (motion blur while scrolling).
I tested all possible combinations of this tree components (PCB, LCD, and digitizer) and I can conclude the reason for the tearing and the motion blur while scrolling is not the LCD but the digitizer! Any combination of components which has the digitizer initially installed with AUO display has the motion blur and tearing, despite of which LCD or mainboard I use. In fact I have now a Sharp with tearing and a smooth AUO. It feels like the sample rate of AUO digitizer is lower or something like that. I don't know if somethig about this could be tweaked in the kernel.