From d6e7fbc4aa17018dd30a7bac1867947d948c9f57 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <fourdan@xfce.org>
Date: Wed, 1 Aug 2018 23:17:38 +0200
Subject: [PATCH] compositor: Use a fence to sync X and GL
Bug: 13519
Use a fence to prevent the pixmap updates to be picked up before
being complete, which causes visual glitches and blinking.
Signed-off-by: Olivier Fourdan <fourdan@xfce.org>
---
src/compositor.c | 51 ++++++++++++++++++++++++++++++++++++++++++------
src/screen.h | 3 +++
2 files changed, 48 insertions(+), 6 deletions(-)
diff --git a/src/compositor.c b/src/compositor.c
index 8cbe17518..500f68fd6 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -39,6 +39,9 @@
#ifdef HAVE_EPOXY
#include <epoxy/gl.h>
#include <epoxy/glx.h>
+#ifdef HAVE_XSYNC_EXTENSION
+#include <X11/extensions/sync.h>
+#endif /* HAVE_XSYNC_EXTENSION */
#endif /* HAVE_EPOXY */
#ifdef HAVE_PRESENT_EXTENSION
@@ -1449,6 +1452,40 @@ unbind_glx_texture (ScreenInfo *screen_info)
check_gl_error();
}
+static void
+fence_sync_pixmap (ScreenInfo *screen_info, Pixmap pixmap)
+{
+#ifdef HAVE_XSYNC
+ Bool triggered = False;
+
+ if (screen_info->fence == None)
+ {
+ screen_info->fence = XSyncCreateFence (myScreenGetXDisplay (screen_info), pixmap, FALSE);
+ }
+ if (!screen_info->fence)
+ {
+ TRACE ("Cannot create fence\n");
+ return;
+ }
+ if (!XSyncQueryFence(myScreenGetXDisplay (screen_info),
+ screen_info->fence, &triggered))
+ {
+ TRACE ("Cannot query fence\n");
+ return;
+ }
+ if (triggered)
+ {
+ TRACE ("Fence already triggered\n");
+ return;
+ }
+ TRACE ("Awaiting fence of drawable 0x%x\n", pixmap);
+ XSyncTriggerFence(myScreenGetXDisplay (screen_info), screen_info->fence);
+ XSyncAwaitFence(myScreenGetXDisplay (screen_info), &screen_info->fence, 1);
+ XSyncResetFence(myScreenGetXDisplay (screen_info), screen_info->fence);
+ TRACE ("Fence for drawable 0x%x cleared\n", pixmap);
+#endif /* HAVE_XSYNC */
+}
+
static void
bind_glx_texture (ScreenInfo *screen_info, Pixmap pixmap)
{
@@ -1465,7 +1502,6 @@ bind_glx_texture (ScreenInfo *screen_info, Pixmap pixmap)
{
screen_info->glx_drawable = create_glx_drawable (screen_info, pixmap);
}
-
TRACE ("(re)Binding GLX pixmap 0x%lx to texture 0x%x",
screen_info->glx_drawable, screen_info->rootTexture);
enable_glx_texture (screen_info);
@@ -1501,9 +1537,6 @@ redraw_glx_texture (ScreenInfo *screen_info)
TRACE ("(re)Drawing GLX pixmap 0x%lx/texture 0x%x",
screen_info->glx_drawable, screen_info->rootTexture);
- /* Make sure previous updates are completed */
- glXWaitX ();
-
glMatrixMode(GL_TEXTURE);
glPushMatrix();
@@ -1551,8 +1584,6 @@ redraw_glx_texture (ScreenInfo *screen_info)
glXReleaseTexImageEXT (myScreenGetXDisplay (screen_info),
screen_info->glx_drawable, GLX_FRONT_EXT);
- glXWaitGL ();
-
check_gl_error();
}
#endif /* HAVE_EPOXY */
@@ -2212,6 +2243,8 @@ paint_all (ScreenInfo *screen_info, XserverRegion region, gushort buffer)
#ifdef HAVE_EPOXY
if (screen_info->use_glx)
{
+ fence_sync_pixmap (screen_info,
+ screen_info->rootPixmap[buffer]);
bind_glx_texture (screen_info,
screen_info->rootPixmap[buffer]);
redraw_glx_texture (screen_info);
@@ -4368,6 +4401,9 @@ compositorManageScreen (ScreenInfo *screen_info)
#ifdef HAVE_EPOXY
screen_info->use_glx = !screen_info->use_present &&
+#ifdef HAVE_XSYNC
+ display_info->have_xsync &&
+#endif /* HAVE_XSYNC */
(display_info->vblank_method == VBLANK_AUTO ||
display_info->vblank_method == VBLANK_GLX);
@@ -4378,6 +4414,9 @@ compositorManageScreen (ScreenInfo *screen_info)
screen_info->rootTexture = None;
screen_info->glx_drawable = None;
screen_info->texture_filter = GL_LINEAR;
+#ifdef HAVE_XSYNC
+ screen_info->fence = None;
+#endif /* HAVE_XSYNC */
screen_info->use_glx = init_glx (screen_info);
}
#else /* HAVE_EPOXY */
diff --git a/src/screen.h b/src/screen.h
index 14a2d8443..01bc61cbc 100644
--- a/src/screen.h
+++ b/src/screen.h
@@ -217,6 +217,9 @@ struct _ScreenInfo
GLXFBConfig glx_fbconfig;
GLXContext glx_context;
GLXWindow glx_window;
+#ifdef HAVE_XSYNC
+ XSyncFence fence;
+#endif /* HAVE_XSYNC */
#endif /* HAVE_EPOXY */
#ifdef HAVE_PRESENT_EXTENSION
--
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