commit df043a729bc7098bd27663d4639951e1e8409369
Author: Fabrice Bellet <fabrice@bellet.info>
Date:   Sun Feb 28 23:55:57 2016 +0100

    intel: use the same bufmgr when opening the same device
    
    Relocation when bo use a different bufmgr are not accepted
    in the intel drm driver. This happens when two GL contexts
    are created, one from cogl, and one from vaapi for example.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71759

diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index 0a4012b..cb463be 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -3268,13 +3268,24 @@ drm_intel_bufmgr_gem_set_aub_annotations(drm_intel_bo *bo,
 static pthread_mutex_t bufmgr_list_mutex = PTHREAD_MUTEX_INITIALIZER;
 static drmMMListHead bufmgr_list = { &bufmgr_list, &bufmgr_list };
 
+static int
+compare_file_descriptor(int fd1, int fd2) {
+	struct stat stat1, stat2;
+	if (fstat (fd1, &stat1) < 0)
+		return -1;
+	if (fstat (fd2, &stat2) < 0)
+		return -1;
+	return (stat1.st_dev == stat2.st_dev) && (stat1.st_ino == stat2.st_ino);
+}
+
 static drm_intel_bufmgr_gem *
 drm_intel_bufmgr_gem_find(int fd)
 {
 	drm_intel_bufmgr_gem *bufmgr_gem;
 
 	DRMLISTFOREACHENTRY(bufmgr_gem, &bufmgr_list, managers) {
-		if (bufmgr_gem->fd == fd) {
+		if (bufmgr_gem->fd == fd ||
+		    compare_file_descriptor (bufmgr_gem->fd, fd)) {
 			atomic_inc(&bufmgr_gem->refcount);
 			return bufmgr_gem;
 		}