diff --git a/glamor/glamor_egl.c b/glamor/glamor_egl.c
index 2ea3efc58..4a550932a 100644
--- a/glamor/glamor_egl.c
+++ b/glamor/glamor_egl.c
@@ -35,6 +35,7 @@
 #include <sys/ioctl.h>
 #include <errno.h>
 #include <xf86.h>
+#include <xf86Priv.h>
 #include <xf86drm.h>
 #define EGL_DISPLAY_NO_X_MESA
 
@@ -960,7 +961,8 @@ glamor_egl_init(ScrnInfoPtr scrn, int fd)
                                 "EGL_EXT_image_dma_buf_import") &&
         epoxy_has_egl_extension(glamor_egl->display,
                                 "EGL_EXT_image_dma_buf_import_modifiers"))
-        glamor_egl->dmabuf_capable = TRUE;
+        glamor_egl->dmabuf_capable = !!strstr(xf86Info.debug,
+                                              "dmabuf_capable");
 #endif
 
     glamor_egl->saved_free_screen = scrn->FreeScreen;
diff --git a/hw/xfree86/man/xorg.conf.man b/hw/xfree86/man/xorg.conf.man
index 46ddd0ec9..958926243 100644
--- a/hw/xfree86/man/xorg.conf.man
+++ b/hw/xfree86/man/xorg.conf.man
@@ -498,6 +498,9 @@ The options recognised by this section are:
 .BI "Option \*qDebug\*q  \*q" string \*q
 This comma-separated list provides a way to control various debugging switches
 from the config file.
+At the moment the only defined value is
+.B dmabuf_capable
+which instructs glamor to enable some unstable buffer management code.
 .TP 7
 .BI "Option \*qDefaultServerLayout\*q  \*q" layout\-id \*q
 This specifies the default