[PATCH v2] wayland: Add support for eglSwapInterval
Neil Roberts
neil at linux.intel.com
Thu Sep 12 08:58:56 PDT 2013
I like Kristian's proposal to throttle the swap buffers to sync
callbacks. It has the added benefit that we can stop the client from
unnecessarily using 3 buffers by waiting for the sync event in
get_back_bo. The previous patch would cause the client to use three
buffers because it would only block when all three buffer slots are
full. It also means if the compositor is doing something weird and
keeping all three buffers then the render will fail instead of
blocking forever, which I think makes more sense.
Daniel, is there any situation where the compositor would keep hold of
more than one before? If not, surely whenever you attach and commit a
new buffer you will get the release event for the old buffer
immediately? If that's the case then I don't think there'd be any need
to periodically send sync requests to the compositor.
It doesn't look like the old patch has landed in master yet, so here
is a version 2 of the patch which implements Kristian's suggestion.
Regards,
- Neil
-- >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. It needs to at least throttle itself to that so that it will still be
sure to receive buffer release events.
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.
---
src/egl/drivers/dri2/egl_dri2.h | 7 ++
src/egl/drivers/dri2/platform_wayland.c | 127 ++++++++++++++++++++++++++++++--
src/egl/drivers/dri2/platform_x11.c | 6 --
3 files changed, 126 insertions(+), 14 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
int dx;
int dy;
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..1cb92ac 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;
@@ -261,8 +271,20 @@ 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 of reusing a buffer */
+ do {
+ if (wl_display_dispatch_queue(dri2_dpy->wl_dpy,
+ dri2_dpy->wl_queue) == -1)
+ return EGL_FALSE;
+ } while (dri2_surf->throttle_callback != NULL);
+ }
if (dri2_surf->back == NULL) {
for (i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
@@ -452,6 +474,21 @@ static const struct wl_callback_listener frame_listener = {
};
static void
+wayland_throttle_callback(void *data,
+ struct wl_callback *callback,
+ uint32_t time)
+{
+ struct dri2_egl_surface *dri2_surf = data;
+
+ dri2_surf->throttle_callback = NULL;
+ wl_callback_destroy(callback);
+}
+
+static const struct wl_callback_listener throttle_listener = {
+ wayland_throttle_callback
+};
+
+static void
create_wl_buffer(struct dri2_egl_surface *dri2_surf)
{
struct dri2_egl_display *dri2_dpy =
@@ -511,11 +548,14 @@ dri2_swap_buffers_with_damage(_EGLDriver *drv,
if (ret < 0)
return EGL_FALSE;
- dri2_surf->frame_callback = wl_surface_frame(dri2_surf->wl_win->surface);
- wl_callback_add_listener(dri2_surf->frame_callback,
- &frame_listener, dri2_surf);
- wl_proxy_set_queue((struct wl_proxy *) dri2_surf->frame_callback,
- dri2_dpy->wl_queue);
+ if (draw->SwapInterval > 0) {
+ dri2_surf->frame_callback =
+ wl_surface_frame(dri2_surf->wl_win->surface);
+ wl_callback_add_listener(dri2_surf->frame_callback,
+ &frame_listener, dri2_surf);
+ wl_proxy_set_queue((struct wl_proxy *) dri2_surf->frame_callback,
+ dri2_dpy->wl_queue);
+ }
for (i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++)
if (dri2_surf->color_buffers[i].age > 0)
@@ -559,6 +599,18 @@ dri2_swap_buffers_with_damage(_EGLDriver *drv,
wl_surface_commit(dri2_surf->wl_win->surface);
+ if (draw->SwapInterval == 0) {
+ /* If we're not throttling to the frame callback we'll at least throttle
+ * to sync events from the server so that it has a chance to send us
+ * buffer release events. */
+ dri2_surf->throttle_callback = wl_display_sync(dri2_dpy->wl_dpy);
+ wl_callback_add_listener(dri2_surf->throttle_callback,
+ &throttle_listener, dri2_surf);
+ wl_proxy_set_queue((struct wl_proxy *) dri2_surf->throttle_callback,
+ dri2_dpy->wl_queue);
+
+ }
+
(*dri2_dpy->flush->flush)(dri2_surf->dri_drawable);
(*dri2_dpy->flush->invalidate)(dri2_surf->dri_drawable);
@@ -802,6 +854,60 @@ static const struct wl_registry_listener registry_listener = {
registry_handle_global_remove
};
+static EGLBoolean
+dri2_swap_interval(_EGLDriver *drv,
+ _EGLDisplay *disp,
+ _EGLSurface *surf,
+ EGLint interval)
+{
+ if (interval > surf->Config->MaxSwapInterval)
+ interval = surf->Config->MaxSwapInterval;
+ else if (interval < surf->Config->MinSwapInterval)
+ interval = surf->Config->MinSwapInterval;
+
+ surf->SwapInterval = interval;
+
+ return EGL_TRUE;
+}
+
+static void
+dri2_setup_swap_interval(struct dri2_egl_display *dri2_dpy)
+{
+ GLint vblank_mode = DRI_CONF_VBLANK_DEF_INTERVAL_1;
+
+ /* We can't use values greater than 1 on Wayland because we are using the
+ * frame callback to synchronise the frame and the only way we be sure to
+ * get a frame callback is to attach a new buffer. Therefore we can't just
+ * sit drawing nothing to wait until the next ‘n’ frame callbacks */
+
+ if (dri2_dpy->config)
+ dri2_dpy->config->configQueryi(dri2_dpy->dri_screen,
+ "vblank_mode", &vblank_mode);
+ switch (vblank_mode) {
+ case DRI_CONF_VBLANK_NEVER:
+ dri2_dpy->min_swap_interval = 0;
+ dri2_dpy->max_swap_interval = 0;
+ dri2_dpy->default_swap_interval = 0;
+ break;
+ case DRI_CONF_VBLANK_ALWAYS_SYNC:
+ dri2_dpy->min_swap_interval = 1;
+ dri2_dpy->max_swap_interval = 1;
+ dri2_dpy->default_swap_interval = 1;
+ break;
+ case DRI_CONF_VBLANK_DEF_INTERVAL_0:
+ dri2_dpy->min_swap_interval = 0;
+ dri2_dpy->max_swap_interval = 1;
+ dri2_dpy->default_swap_interval = 0;
+ break;
+ default:
+ case DRI_CONF_VBLANK_DEF_INTERVAL_1:
+ dri2_dpy->min_swap_interval = 0;
+ dri2_dpy->max_swap_interval = 1;
+ dri2_dpy->default_swap_interval = 1;
+ break;
+ }
+}
+
EGLBoolean
dri2_initialize_wayland(_EGLDriver *drv, _EGLDisplay *disp)
{
@@ -817,6 +923,7 @@ dri2_initialize_wayland(_EGLDriver *drv, _EGLDisplay *disp)
drv->API.DestroySurface = dri2_destroy_surface;
drv->API.SwapBuffers = dri2_swap_buffers;
drv->API.SwapBuffersWithDamageEXT = dri2_swap_buffers_with_damage;
+ drv->API.SwapInterval = dri2_swap_interval;
drv->API.Terminate = dri2_terminate;
drv->API.QueryBufferAge = dri2_query_buffer_age;
drv->API.CreateWaylandBufferFromImageWL =
@@ -876,9 +983,13 @@ dri2_initialize_wayland(_EGLDriver *drv, _EGLDisplay *disp)
dri2_dpy->extensions[2] = &use_invalidate.base;
dri2_dpy->extensions[3] = NULL;
+ dri2_dpy->swap_available = EGL_TRUE;
+
if (!dri2_create_screen(disp))
goto cleanup_driver;
+ dri2_setup_swap_interval(dri2_dpy);
+
/* The server shouldn't advertise WL_DRM_CAPABILITY_PRIME if the driver
* doesn't have createImageFromFds, since we're using the same driver on
* both sides. We don't want crash if that happens anyway, so fall back to
diff --git a/src/egl/drivers/dri2/platform_x11.c b/src/egl/drivers/dri2/platform_x11.c
index ec76aec..f2cd4fc 100644
--- a/src/egl/drivers/dri2/platform_x11.c
+++ b/src/egl/drivers/dri2/platform_x11.c
@@ -39,12 +39,6 @@
#include "egl_dri2.h"
-/* 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
-
static void
swrastCreateDrawable(struct dri2_egl_display * dri2_dpy,
struct dri2_egl_surface * dri2_surf,
--
1.8.3.1
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