I can happily report that (for IA-32 at least) those proposed -11 kernel seems to work for me (as does 2.6.28-rc8 which I'm using from day to day).
I also discovered that even the -9 kernel that's currently out there doesn't have the problem if you don't have desktop effects enabled in KDE4 (obviously because at that point you're not using DRI).
I can happily report that (for IA-32 at least) those proposed -11 kernel seems to work for me (as does 2.6.28-rc8 which I'm using from day to day).
I also discovered that even the -9 kernel that's currently out there doesn't have the problem if you don't have desktop effects enabled in KDE4 (obviously because at that point you're not using DRI).