[cogl/cogl-1.22] kms-winsys: don't disable page flipping on EACCES

[Ray Strode <halfline src gnome org>]

commit 6bd49c3dc87502534834b773490de355789179c9
Author: Ray Strode <rstrode redhat com>
Date:   Wed Aug 26 17:02:45 2015 -0400

    kms-winsys: don't disable page flipping on EACCES
    
    If the user switches VTs in the middle of a page flip, the
    page flip operation may fail with EACCES. page flipping will
    work next time the VT becomes active, so we shouldn't disable
    page flipping in that case.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754540

 cogl/winsys/cogl-winsys-egl-kms.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/cogl/winsys/cogl-winsys-egl-kms.c b/cogl/winsys/cogl-winsys-egl-kms.c
index 683bbc8..20c325c 100644
--- a/cogl/winsys/cogl-winsys-egl-kms.c
+++ b/cogl/winsys/cogl-winsys-egl-kms.c
@@ -40,6 +40,7 @@
 
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
+#include <errno.h>
 #include <stddef.h>
 #include <drm.h>
 #include <xf86drm.h>
@@ -601,7 +602,7 @@ flip_all_crtcs (CoglDisplay *display, CoglFlipKMS *flip, int fb_id)
           ret = drmModePageFlip (kms_renderer->fd,
                                  crtc->id, fb_id,
                                  DRM_MODE_PAGE_FLIP_EVENT, flip);
-          if (ret)
+          if (ret != 0 && ret != -EACCES)
             {
               g_warning ("Failed to flip: %m");
               kms_renderer->page_flips_not_supported = TRUE;