R9270X kernel drm-fixes-3.17-wip xorg Jun, but ddx/glamor head.

Tentatively, since -

commit bbbe3b65adee44c164532d7afb4ff8fd8f88bbf4
Author: Eric Anholt <eric@anholt.net>
Date:   Fri Aug 22 10:34:55 2014 -0700

    u_vbuf: Simplify the format fallback translation.
    
    Individual caps made supporting new fallbacks more complicated than it
    needed to be.  Instead, just make a table of fallbacks at context init
    time.
    
    v2: Fix inverted "do we need to install vbuf?" flagging caught by Marek.

There is a chance when I startx that rendering will be broken.

Fluxbox menues empty, screen black, can blindly use menu to start an xterm.

xterm OK at first look - maximised OK dmesg worked and showed nothing strange, but trying to scroll up only updated the top 5 lines scrolling down only bottom 5.

tool bar and menu bar not being cleared, nothing rendered with glxgears.

mplayer video just first frame status line progressing as if normal.

This doesn't always happen, need quit/restart X several times to get bad during bisect. Goods were tested 20 ish times so there's a small chance I got a false good.

Xorg log normal.