[Mesa-dev] [PATCH] dri_util: fallback to core with drivers not supporting compat for 3.1

[Andres Gomez]

2599b92eb97 changed Mesa's behavior to allow Compatiblity profile with
3.1, and fail when the driver doesn't implement it, if the Core
profile is not requested by applications.

Formerly, when requesting a 3.1 Compatibility profile Mesa would
always fall back into a Core profile. We go back to that behavior now
so, if the specific driver is not supporting 3.1 with Compatibility
profile, we will keep falling back into 3.1 Core.

Fixes: a0c8b49284e ("mesa: enable OpenGL 3.1 with ARB_compatibility")

Cc: Marek Olšák <marek.olsak at amd.com>
Cc: Ian Romanick <ian.d.romanick at intel.com>
Cc: Kenneth Graunke <kenneth at whitecape.org>
Cc: Eric Engestrom <eric.engestrom at imgtec.com>
Cc: Emil Velikov <emil.velikov at collabora.com>
Signed-off-by: Andres Gomez <agomez at igalia.com>
---
 docs/features.txt                      |  4 ++--
 src/mesa/drivers/dri/common/dri_util.c | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/docs/features.txt b/docs/features.txt
index 5eae34bf0df..d53dd805b1d 100644
--- a/docs/features.txt
+++ b/docs/features.txt
@@ -25,8 +25,8 @@ not started
 # OpenGL Core and Compatibility context support
 
 Some drivers do not support the Compatibility profile or ARB_compatibility.
-Such drivers are limited to OpenGL 3.0 if the Core profile is not requested
-by applications. Some of the later GL features are exposed in the 3.0 context
+Such drivers are limited to use OpenGL 3.1 and later in Core
+profile. Some of the later GL features are exposed in the 3.0 context
 as extensions.
 
 
diff --git a/src/mesa/drivers/dri/common/dri_util.c b/src/mesa/drivers/dri/common/dri_util.c
index a34f38d6114..53461dfb4e0 100644
--- a/src/mesa/drivers/dri/common/dri_util.c
+++ b/src/mesa/drivers/dri/common/dri_util.c
@@ -381,6 +381,16 @@ driCreateContextAttribs(__DRIscreen *screen, int api,
 	}
     }
 
+    /* The specific Mesa driver may not support the GL_ARB_compatibilty
+     * extension or the compatibility profile.  In that case, we treat an
+     * API_OPENGL_COMPAT 3.1 as API_OPENGL_CORE. We reject API_OPENGL_COMPAT
+     * 3.2+ in any case.
+     */
+    if (mesa_api == API_OPENGL_COMPAT &&
+        ctx_config.major_version == 3 && ctx_config.minor_version == 1 &&
+        screen->max_gl_compat_version < 31)
+       mesa_api = API_OPENGL_CORE;
+
     if (mesa_api == API_OPENGL_COMPAT
         && ((ctx_config.major_version > 3)
             || (ctx_config.major_version == 3 &&
-- 
2.16.1