From 1943b8e544a985e08cd4fbe2ae79320fed2f2548 Mon Sep 17 00:00:00 2001
From: Emmanuele Bassi <ebassi@linux.intel.com>
Date: Mon, 9 Aug 2010 11:29:03 +0100
Subject: [PATCH] glx: Depend on libdrm

DRM is available on more platforms than Linux (e.g. kFreeBSD), but
Clutter currently FTBFS there because of not being an alternative to
the __linux__ code (where it should be HAVE_DRM).

Instead of copying the DRM data structures, we should use libdrm when
falling back to directly requesting to wait for the vblank.

http://bugzilla.clutter-project.org/show_bug.cgi?id=2225

Based on a patch by: Emilio Pozuelo Monfort <pochu27@gmail.com>
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
---
 clutter/glx/clutter-stage-glx.c | 43 +++++++++------------------------
 configure.ac                    |  8 ++++++
 2 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/clutter/glx/clutter-stage-glx.c b/clutter/glx/clutter-stage-glx.c
index 42e488e90..06010da58 100644
--- a/clutter/glx/clutter-stage-glx.c
+++ b/clutter/glx/clutter-stage-glx.c
@@ -53,32 +53,9 @@
 #include <fcntl.h>
 #include <errno.h>
 
-#ifdef __linux__
-#define DRM_VBLANK_RELATIVE 0x1;
-
-struct drm_wait_vblank_request {
-    int           type;
-    unsigned int  sequence;
-    unsigned long signal;
-};
-
-struct drm_wait_vblank_reply {
-    int          type;
-    unsigned int sequence;
-    long         tval_sec;
-    long         tval_usec;
-};
-
-typedef union drm_wait_vblank {
-    struct drm_wait_vblank_request request;
-    struct drm_wait_vblank_reply reply;
-} drm_wait_vblank_t;
-
-#define DRM_IOCTL_BASE                  'd'
-#define DRM_IOWR(nr,type)               _IOWR(DRM_IOCTL_BASE,nr,type)
-#define DRM_IOCTL_WAIT_VBLANK           DRM_IOWR(0x3a, drm_wait_vblank_t)
-
-#endif /* __linux__ */
+#ifdef HAVE_DRM
+#include <drm.h>
+#endif
 
 static void clutter_stage_window_iface_init (ClutterStageWindowIface *iface);
 
@@ -462,7 +439,7 @@ clutter_stage_window_iface_init (ClutterStageWindowIface *iface)
   /* the rest is inherited from ClutterStageX11 */
 }
 
-#ifdef __linux__
+#ifdef HAVE_DRM
 static int
 drm_wait_vblank(int fd, drm_wait_vblank_t *vbl)
 {
@@ -471,14 +448,14 @@ drm_wait_vblank(int fd, drm_wait_vblank_t *vbl)
     do
       {
         ret = ioctl(fd, DRM_IOCTL_WAIT_VBLANK, vbl);
-        vbl->request.type &= ~DRM_VBLANK_RELATIVE;
+        vbl->request.type &= ~_DRM_VBLANK_RELATIVE;
         rc = errno;
       }
     while (ret && rc == EINTR);
 
     return rc;
 }
-#endif /* __linux__ */
+#endif /* HAVE_DRM */
 
 static void
 wait_for_vblank (ClutterBackendGLX *backend_glx)
@@ -496,18 +473,20 @@ wait_for_vblank (ClutterBackendGLX *backend_glx)
                                     (retraceCount + 1) % 2,
                                     &retraceCount);
     }
-#ifdef __linux__
   else
     {
+#ifdef HAVE_DRM
       drm_wait_vblank_t blank;
 
       CLUTTER_NOTE (BACKEND, "Waiting for vblank (drm)");
-      blank.request.type     = DRM_VBLANK_RELATIVE;
+      blank.request.type     = _DRM_VBLANK_RELATIVE;
       blank.request.sequence = 1;
       blank.request.signal   = 0;
       drm_wait_vblank (backend_glx->dri_fd, &blank);
+#else
+      CLUTTER_NOTE (BACKEND, "No vblank mechanism found");
+#endif /* HAVE_DRM */
     }
-#endif
 }
 
 void
diff --git a/configure.ac b/configure.ac
index 4a124b62d..0e7a92996 100644
--- a/configure.ac
+++ b/configure.ac
@@ -180,6 +180,14 @@ AS_CASE([$CLUTTER_FLAVOUR],
                            # if a pkg-config file isn't found just add -lGL
                            # and hope for the best.
                            [FLAVOUR_LIBS="$FLAVOUR_LIBS -lGL"])
+
+          # We might fall back to DRM for sync-to-vblank on GLX
+          PKG_CHECK_EXISTS([libdrm],
+                           [
+                             AC_DEFINE([HAVE_DRM], [1], [Have libdrm support])
+                             BACKEND_PC_FILES="$BACKEND_PC_FILES libdrm"
+                           ],
+                           [])
         ],
 
         [opengl-egl-xlib],