Mesa (staging/19.1): egl: Make the 565 pbuffer-only config single buffered.

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Module: Mesa
Branch: staging/19.1
Commit: f8c0b90f993ff5277ed90bb59da31648fcd5dd4e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f8c0b90f993ff5277ed90bb59da31648fcd5dd4e

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Fri Mar 22 18:00:55 2019 -0700

egl: Make the 565 pbuffer-only config single buffered.

In commit dacb11a585face5ca179c34cfc588a71a425c1e0, Eric found the first
matching 565 pbuffer config, and stopped.  Our double-buffered configs
come first in the list, so we added that, making a pbuffer-only config
that claimed to be double buffered.  This doesn't make sense, since
pixmaps/pbuffers are fundamentally not double buffered.

When using that config, every call to eglCreatePbufferSurface would fail
with EGL_BAD_MATCH.  The call chain looks like this:

   - eglCreatePbufferSurface
   - dri3_create_pbuffer_surface
   - dri3_create_surface
   - dri2_get_dri_config

which eventually does:

   const bool double_buffer = surface_type == EGL_WINDOW_BIT;

and then fails to find a matching config, because it ends up looking
for a single-buffered config - and there aren't any.

To fix this, make the 565 pbuffer config single-buffered.  This fixes
at least 51 dEQP-EGL.* tests.

Fixes: dacb11a585f ("egl: Add a 565 pbuffer-only EGL config under X11.")
Reviewed-by: Eric Engestrom <eric.engestrom at intel.com>
Reviewed-by: Eric Anholt <eric at anholt.net>
(cherry picked from commit 6ad31c4ff33d92f6359b196a94ace99682272111)

---

 src/egl/drivers/dri2/platform_x11.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/egl/drivers/dri2/platform_x11.c b/src/egl/drivers/dri2/platform_x11.c
index 081c9c8f219..c30b8ea085d 100644
--- a/src/egl/drivers/dri2/platform_x11.c
+++ b/src/egl/drivers/dri2/platform_x11.c
@@ -861,13 +861,17 @@ dri2_x11_add_configs_for_visuals(struct dri2_egl_display *dri2_dpy,
          0,
       };
 
-      /* Check that we've found single-sample, no depth, no stencil. */
+      /* Check that we've found single-sample, no depth, no stencil,
+       * and single-buffered.
+       */
       if (!dri2_x11_config_match_attrib(dri2_dpy, config,
                                         __DRI_ATTRIB_DEPTH_SIZE, 0) ||
           !dri2_x11_config_match_attrib(dri2_dpy, config,
                                         __DRI_ATTRIB_STENCIL_SIZE, 0) ||
           !dri2_x11_config_match_attrib(dri2_dpy, config,
-                                        __DRI_ATTRIB_SAMPLES, 0)) {
+                                        __DRI_ATTRIB_SAMPLES, 0) ||
+          !dri2_x11_config_match_attrib(dri2_dpy, config,
+                                        __DRI_ATTRIB_DOUBLE_BUFFER, 0)) {
          continue;
       }