kernel-3.15 series fail to load gnome desktop

[Clyde E. Kunkel]

With all of the kernels in the rawhide 3.15 series so far the gnome
desktop fails to load.  Kernels in the 3.14 series are fine.

All I can see is that the X server seems to start (ps -A | grep Xorg
returns a PID), but the Xorg.0.log is empty.  No obvious failures in
journalctl -xb.  I see gdm is started, but at this point lots of disk
activity but then nothing.  c-a-f2 gets me to tty and I can login.  Top
looks normal for a non-gnome session.  Killing X sometimes brings up
the GDM login, but after entering password, just a blank screen and the
Xorg log file is still empty.

Have tried every 3.15 kernel so far without luck.

I don't see any obvious bz, and would be happy to enter one, but don't
know what information should be included.

Any help appreciated.

TIA