[PATCH xserver] fb: Check whether the window is enabled directly

[Adam Jackson]

On Tue, 2017-09-12 at 14:40 -0700, Keith Packard wrote:
> Adam Jackson <ajax at redhat.com> writes:
> 
> > ... instead of its root window. Xwayland's rootless mode empties the
> > root window border clip since its root window has no storage, but
> > redirected windows (the only kind it can show) will have a non-empty
> > border clip anyway, cf. the #ifdef COMPOSITE in miComputeClips. With
> > this change, non-glamor Xwayland's GetImage actually works.
> > 
> > Other acceleration layers may need to change to account for this, but
> > this appears to be safe for the existing open source drivers. Only the
> > xfree86 DDX has any problem with losing its framebuffer on VT switch,
> > and even then only for UMS drivers (which excludes glamor, uxa, and sna
> > from consideration). This leaves exa, which already contains code to
> > evict pixmaps to host memory on VT switch. Since the xfree86 core will
> > still empty the root clip on VT switch, while the root window itself may
> > not contain a valid image we won't try to touch it, but GetImage from a
> > redirected window will now work even when switched away.
> > 
> > Signed-off-by: Adam Jackson <ajax at redhat.com>
> 
> Acked-by: Keith Packard <keithp at keithp.com>

Merged this, and marked Emmanuel's patches as superceded in patchwork,
as I think this change is all that's needed. If I'm wrong about that
please do yell.

- ajax