Thomas Hellstrom authored Sep 26, 2017 and Adam Jackson committed Dec 20, 2017

Previously, before GLX_OML_swap_method was fixed, both the X server and
client ignored the swapMethod fbconfig value, which meant that, if the dri
driver thought it exposed more than one swapMethod, it actually just
exported a duplicated set of fbconfigs. When fixing GLX_OML_swap_method
and restricting the choice for built-in visuals to a single swap method
that meant we didn't have that many fbconfigs to choose from when pairing
the compositing visual with an fbconfig, resulting in the fbconfig paired
with the compositing visual becoming too restrictive for some applications,
(at least for kwin). This problem would also happen if the dri driver
only exposed a single swap method to begin with.

So, to make sure the compositing visual gets a good enough fbconfig,
duplicate fbconfigs that are suitable for compositing visuals and make
sure these duplicated fbconfigs can be used only by compositing visuals.
For duplicated fbconfigs not paired with a compositing visual, construct
new compositing visuals, making compositing clients able to choose visuals
/ fbconfig more adapted to their needs.

This is in some sense equivalent to adding a new "TRUECOLOR_COMPOSITING"
GLX visualtype.

Fixes: 4486d199 ("glx: Fix visual fbconfig matching with respect to
                      swap method")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102806


Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Tested-By: Nick Sarnie <commendsarnex@gmail.com>
Tested-by: Fredrik Höglund <fredrik@kde.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
(cherry picked from commit f84e59a4)