diff --git a/include/epoxy/glx_common.h b/include/epoxy/glx_common.h
index c23ec72..4ad08c7 100644
--- a/include/epoxy/glx_common.h
+++ b/include/epoxy/glx_common.h
@@ -34,7 +34,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
-bool epoxy_has_glx_extension(const char *extension);
+bool epoxy_has_glx_extension(Display *dpy, int screen, const char *extension);
 int epoxy_glx_version(Display *dpy, int screen);
 
 #endif /* EPOXY_GLX_COMMON_H */
diff --git a/src/dispatch_common.c b/src/dispatch_common.c
index a32b30b..31885fb 100644
--- a/src/dispatch_common.c
+++ b/src/dispatch_common.c
@@ -212,17 +212,29 @@ epoxy_has_egl_extension(const char *ext)
 }
 #endif
 
-PUBLIC bool
-epoxy_has_glx_extension(const char *ext)
+/**
+ * If we can determine the GLX extension support from the current
+ * context, then return that, otherwise give the answer that will just
+ * send us on to get_proc_address().
+ */
+bool
+epoxy_conservative_has_glx_extension(const char *ext)
 {
     Display *dpy = glXGetCurrentDisplay();
-    int screen = 0;
+    GLXContext ctx = glXGetCurrentContext();
+    int screen;
 
-    if (!dpy) {
-        fprintf(stderr, "waffle needs a display!"); /* XXX */
-        return false;
-    }
+    if (!dpy || !ctx)
+        return true;
 
+    glXQueryContext(dpy, ctx, GLX_SCREEN, &screen);
+
+    return epoxy_has_glx_extension(dpy, screen, ext);
+}
+
+PUBLIC bool
+epoxy_has_glx_extension(Display *dpy, int screen, const char *ext)
+{
     /* No, you can't just use glXGetClientString or
      * glXGetServerString() here.  Those each tell you about one half
      * of what's needed for an extension to be supported, and
diff --git a/src/dispatch_common.h b/src/dispatch_common.h
index ed3fa5b..8256134 100644
--- a/src/dispatch_common.h
+++ b/src/dispatch_common.h
@@ -50,6 +50,7 @@ bool epoxy_is_glx(void);
 
 void *epoxy_get_proc_address(const char *name);
 int epoxy_conservative_glx_version(void);
+bool epoxy_conservative_has_glx_extension(const char *name);
 void *epoxy_dlsym(const char *name);
 void epoxy_glx_autoinit(void);
 void epoxy_platform_autoinit(void);
diff --git a/src/gen_dispatch.py b/src/gen_dispatch.py
index 8b9cc54..b052305 100755
--- a/src/gen_dispatch.py
+++ b/src/gen_dispatch.py
@@ -308,7 +308,7 @@ class Generator(object):
             apis = extension.get('supported').split('|')
             if 'glx' in apis:
                 human_name = 'GLX extension \\"{0}\\"'.format(extname)
-                condition = 'epoxy_has_glx_extension("{0}")'.format(extname)
+                condition = 'epoxy_conservative_has_glx_extension("{0}")'.format(extname)
                 loader = self.gpa_loader
                 self.process_require_statements(extension, condition, loader, human_name)
             if 'gl' in apis:
diff --git a/test/Makefile.am b/test/Makefile.am
index e282f3f..81263b0 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -38,8 +38,6 @@ TESTS = \
 	headerguards \
 	$()
 
-XFAIL_TESTS = glx_has_extension_nocontext
-
 check_PROGRAMS = $(TESTS)
 
 glx_public_api_LDFLAGS = $(X11_LIBS) $(EPOXY) libglx_common.la
diff --git a/test/glx_has_extension_nocontext.c b/test/glx_has_extension_nocontext.c
index 5aeaa4e..2f87ac3 100644
--- a/test/glx_has_extension_nocontext.c
+++ b/test/glx_has_extension_nocontext.c
@@ -46,10 +46,10 @@ main(int argc, char **argv)
 
     dpy = get_display_or_skip();
 
-    if (!epoxy_has_glx_extension("GLX_ARB_get_proc_address"))
+    if (!epoxy_has_glx_extension(dpy, 0, "GLX_ARB_get_proc_address"))
         errx(1, "Implementation reported absence of GLX_ARB_get_proc_address");
 
-    if (epoxy_has_glx_extension("GLX_ARB_ham_sandwich"))
+    if (epoxy_has_glx_extension(dpy, 0, "GLX_ARB_ham_sandwich"))
         errx(1, "Implementation reported presence of GLX_ARB_ham_sandwich");
 
     return pass != true;
diff --git a/test/glx_public_api.c b/test/glx_public_api.c
index e89a4a4..e38d260 100644
--- a/test/glx_public_api.c
+++ b/test/glx_public_api.c
@@ -91,14 +91,14 @@ test_glx_version(void)
 static bool
 test_glx_extension_supported(void)
 {
-    if (!epoxy_has_glx_extension("GLX_ARB_get_proc_address")) {
+    if (!epoxy_has_glx_extension(dpy, 0, "GLX_ARB_get_proc_address")) {
         fprintf(stderr,
                 "Incorrectly reported no support for GLX_ARB_get_proc_address "
                 "(should always be present in Linux ABI)\n");
         return false;
     }
 
-    if (epoxy_has_glx_extension("GLX_EXT_ham_sandwich")) {
+    if (epoxy_has_glx_extension(dpy, 0, "GLX_EXT_ham_sandwich")) {
         fprintf(stderr,
                 "Incorrectly reported support for GLX_EXT_ham_sandwich\n");
         return false;