Am I using the "ati" or "vesa" driver?

[YuGiOhJCJ Mailing-List]

> > So, maybe a bad option or a missing dependency when I try to compile xorg-server-16.0.
> > 
> > You can see here the full output for the configure line:
> > http://pastebin.com/wYpk5ek4
> 
> (In the future, the config.log file would be more useful)
> 
> The problem is this:
> 
> > checking for GBM... no
> 
> Looking at xserver's configure.ac, it actually requires GBM from Mesa
> 10.2 or newer for building glamor. I think this should be made clearer
> in the configure output.
> 
> If you can't use Mesa 10.2, you'll have to use the standalone glamor
> tree for now.
> 

Thank you.
Upgrading from mesa-9.1.7 (official package in Slackware 14.1) to mesa-10.0.2 was not enough.
So, I have upgraded to mesa-10.2.5.
And very important: the "--enable-gbm" option!
Here is my configure line:
$ ./configure --prefix=/usr --with-egl-platforms=x11,drm --with-gallium-drivers="radeonsi" --enable-gbm --enable-shared-glapi --enable-glx-tls --sysconfdir=/etc --libdir=/usr/lib --mandir=/usr/man --docdir=/usr/doc/mesa-${VERSION} --with-dri-driverdir=/usr/lib/xorg/modules/dri --with-dri-drivers="i915,i965" --disable-llvm-shared-libs

After this, I have compiled xorg-server-1.16.0 and glamor is available now:
$ find /tmp/xorg-server-1.16.0/ -name "*glamor*"
/tmp/xorg-server-1.16.0/usr/include/xorg/glamor.h
/tmp/xorg-server-1.16.0/usr/lib/xorg/modules/libglamoregl.so
/tmp/xorg-server-1.16.0/usr/lib/xorg/modules/libglamoregl.la

OK, so now I have direct rendering:
$ grep Direct /var/log/Xorg.0.log
[111116.450] (II) RADEON(0): Direct rendering enabled

It works :)
Problem solved.