When use xf86-video-intel-2.9.1, it is OK to launch qtdemo.
The attached file is the kernel message when X window freeze.
Created attachment 32468 [details]
Kernel message when error happened.
Can't really say anything intelligent here without kernel version details.
So I'll mark this bug as NEEDINFO until that data arrives, but will also
re-assign to Eric.
Fun, lots of bugs, all fixed. Thank you for the report.