I have a laptop with the Silicon Motion Lynx3DM chip. 4.1.0 works fine, except the xv interface. Vids took up to 100% CPU Usage.
In the X-expertmMailinglist I have read that the xv was broken in 4.1 and should be working in 4.2.0.
A month ago I compiled it myself and 'xvidinfo' found no adaptors. But due to lack of time I couldn't investigate this porblem further. (And yes, X loaded the Xvideo extension)
Unfortunatly, your debs did not find any adaptors either...
I know this is not a top priority, but I want to let you know.