7.2-PRERELEASE X-server hang in "drmwtq"

[Artem Kim]

I checked 7.2 RC2 problem still here.

I found a way to reproduce the problem easily.

I used KDE 4.2.2 composite manager is enabled. The problem occurs when two 
applications run in a way that their window to appear at the same time.

I can reproduce the problem on the cards Radeon 9800 XT (AMD64 UP) and  Radeon 
X550 (AMD64 SMP).