On Fri, 13 Sep 2013 17:04:38 +0100
Neil Roberts n...@linux.intel.com wrote:
Here is another version of the patch which brings back the blocking
when there are no buffers available to cope with the situation where
the compositor isn't immediately releasing buffers. Maybe we could
leave the decision about whether to increase the buffer count to 4 as
a separate patch.
Hi Neil,
yes, I think this approach is how it should work. There are a few
details commented below.
-- 8 --
The Wayland EGL platform now respects the eglSwapInterval value. The value is
clamped to either 0 or 1 because it is difficult (and probably not useful) to
sync to more than 1 redraw.
The main change is that if the swap interval is 0 then instead of installing a
frame callback it will just call the display sync method and throttle itself
to that. When the application is not running fullscreen the compositor is
likely to release the previous buffer immediately so this gives the
application the best chance of reusing the buffer.
If there are no buffers available then instead of returning with an error,
get_back_bo will now block until a buffer becomes available. This is necessary
if the compositor is not releasing buffers immediately. As there are only
three buffers, this could actually mean that the client ends up throttled to
the vblank anyway because Weston can hold on to three buffers when the client
is fullscreen. We could fix this by increasing the buffer count to 4 or
changing Weston and KMS to allow cancelling a pending buffer swap, but for now
this patch ignores that problem.
A good explanation, cool.
This also moves the vblank configuration defines from platform_x11.c to the
common egl_dri2.h header so they can be shared by both platforms.
This little part could be a separate patch, so it could go in already.
---
src/egl/drivers/dri2/egl_dri2.h | 7 ++
src/egl/drivers/dri2/platform_wayland.c | 159
src/egl/drivers/dri2/platform_x11.c | 6 --
3 files changed, 147 insertions(+), 25 deletions(-)
diff --git a/src/egl/drivers/dri2/egl_dri2.h b/src/egl/drivers/dri2/egl_dri2.h
index fba5f81..cc657ba 100644
--- a/src/egl/drivers/dri2/egl_dri2.h
+++ b/src/egl/drivers/dri2/egl_dri2.h
@@ -175,6 +175,7 @@ struct dri2_egl_surface
intdx;
intdy;
struct wl_callback*frame_callback;
+ struct wl_callback*throttle_callback;
int format;
#endif
@@ -221,6 +222,12 @@ struct dri2_egl_image
__DRIimage *dri_image;
};
+/* From xmlpool/options.h, user exposed so should be stable */
+#define DRI_CONF_VBLANK_NEVER 0
+#define DRI_CONF_VBLANK_DEF_INTERVAL_0 1
+#define DRI_CONF_VBLANK_DEF_INTERVAL_1 2
+#define DRI_CONF_VBLANK_ALWAYS_SYNC 3
+
/* standard typecasts */
_EGL_DRIVER_STANDARD_TYPECASTS(dri2_egl)
_EGL_DRIVER_TYPECAST(dri2_egl_image, _EGLImage, obj)
diff --git a/src/egl/drivers/dri2/platform_wayland.c
b/src/egl/drivers/dri2/platform_wayland.c
index ffc5959..6ee6ffb 100644
--- a/src/egl/drivers/dri2/platform_wayland.c
+++ b/src/egl/drivers/dri2/platform_wayland.c
@@ -180,8 +180,16 @@ dri2_create_window_surface(_EGLDriver *drv, _EGLDisplay
*disp,
_EGLConfig *conf, EGLNativeWindowType window,
const EGLint *attrib_list)
{
- return dri2_create_surface(drv, disp, EGL_WINDOW_BIT, conf,
+ struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
+ _EGLSurface *surf;
+
+ surf = dri2_create_surface(drv, disp, EGL_WINDOW_BIT, conf,
window, attrib_list);
+
+ if (surf != NULL)
+ drv-API.SwapInterval(drv, disp, surf,
dri2_dpy-default_swap_interval);
+
+ return surf;
}
/**
@@ -216,6 +224,8 @@ dri2_destroy_surface(_EGLDriver *drv, _EGLDisplay *disp,
_EGLSurface *surf)
if (dri2_surf-frame_callback)
wl_callback_destroy(dri2_surf-frame_callback);
+ if (dri2_surf-throttle_callback)
+ wl_callback_destroy(dri2_surf-throttle_callback);
if (dri2_surf-base.Type == EGL_WINDOW_BIT) {
dri2_surf-wl_win-private = NULL;
@@ -261,24 +271,46 @@ get_back_bo(struct dri2_egl_surface *dri2_surf,
__DRIbuffer *buffer)
__DRIimage *image;
int i, name, pitch;
- /* There might be a buffer release already queued that wasn't processed */
- wl_display_dispatch_queue_pending(dri2_dpy-wl_dpy, dri2_dpy-wl_queue);
+ if (dri2_surf-throttle_callback == NULL) {
+ /* There might be a buffer release already queued that wasn't
processed */
+ wl_display_dispatch_queue_pending(dri2_dpy-wl_dpy,
dri2_dpy-wl_queue);
+ } else {
+ /* If we aren't throttling to the frame callbacks then the compositor
+ * may have sent a release event after the last attach so we'll wait
+ * until the sync for the commit request completes in order to have the
+ * best chance
