[PATCH mesa v5 2/2] wayland: Add support for eglSwapInterval
Neil Roberts
neil at linux.intel.com
Fri Nov 15 05:50:50 PST 2013
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 Mesa won't install a
frame callback so that eglSwapBuffers can be executed as often as necessary.
Instead it will do a sync request after the swap buffers. It will block for
sync complete event in get_back_bo instead of the frame callback. The
compositor is likely to send a release event while processing the new buffer
attach and this makes sure we will receive that before deciding whether to
allocate a new buffer.
If there are no buffers available then instead of returning with an error,
get_back_bo will now poll the compositor by repeatedly sending sync requests
every 10ms. This is a last resort and in theory this shouldn't happen because
there should be no reason for the compositor to hold on to more than three
buffers. That means whenever we attach the fourth buffer we should always get
an immediate release event which should come in with the notification for the
first sync request that we are throttled to.
When the compositor is directly scanning out from the application's buffer it
may end up holding on to three buffers. These are the one that is is currently
scanning out from, one that has been given to DRM as the next buffer to flip
to, and one that has been attached and will be given to DRM as soon as the
previous flip completes. When we attach a fourth buffer to the compositor it
should replace that third buffer so we should get a release event immediately
after that. This patch therefore also changes the number of buffer slots to 4
so that we can accomodate that situation.
If DRM eventually gets a way to cancel a pending page flip then the compositors
can be changed to only need to hold on to two buffers and this value can be
put back to 3.
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 | 10 +-
src/egl/drivers/dri2/platform_wayland.c | 199 +++++++++++++++++++++++++++-----
src/egl/drivers/dri2/platform_x11.c | 6 -
3 files changed, 179 insertions(+), 36 deletions(-)
diff --git a/src/egl/drivers/dri2/egl_dri2.h b/src/egl/drivers/dri2/egl_dri2.h
index 8c303d9..d29dd98 100644
--- a/src/egl/drivers/dri2/egl_dri2.h
+++ b/src/egl/drivers/dri2/egl_dri2.h
@@ -174,7 +174,7 @@ struct dri2_egl_surface
struct wl_egl_window *wl_win;
int dx;
int dy;
- struct wl_callback *frame_callback;
+ struct wl_callback *throttle_callback;
int format;
#endif
@@ -194,7 +194,7 @@ struct dri2_egl_surface
#endif
int locked;
int age;
- } color_buffers[3], *back, *current;
+ } color_buffers[4], *back, *current;
#endif
#ifdef HAVE_ANDROID_PLATFORM
@@ -220,6 +220,12 @@ 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 5ce8981..fca35db 100644
--- a/src/egl/drivers/dri2/platform_wayland.c
+++ b/src/egl/drivers/dri2/platform_wayland.c
@@ -34,6 +34,7 @@
#include <unistd.h>
#include <fcntl.h>
#include <xf86drm.h>
+#include <poll.h>
#include "egl_dri2.h"
@@ -183,8 +184,16 @@ 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;
}
/**
@@ -217,8 +226,8 @@ dri2_destroy_surface(_EGLDriver *drv, _EGLDisplay *disp, _EGLSurface *surf)
dri2_dpy->dri2->releaseBuffer(dri2_dpy->dri_screen,
dri2_surf->dri_buffers[i]);
- 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;
@@ -257,41 +266,99 @@ dri2_release_buffers(struct dri2_egl_surface *dri2_surf)
}
static int
+poll_compositor(struct dri2_egl_display *dri2_dpy)
+{
+ static GLboolean seen_wait_warning = GL_FALSE;
+ struct pollfd pollfd;
+
+ /* This path is a last resort and it implies that something has gone wrong
+ * so we'll warn about it */
+ if (!seen_wait_warning) {
+ _eglLog(_EGL_WARNING, "waiting for the compositor to release a buffer");
+ seen_wait_warning = GL_TRUE;
+ }
+
+ /* The plan here is that we'll wait for up to 10ms for some data from the
+ * compositor. If so we'll just return so that it will check if there is
+ * now a buffer available. Otherwise we'll wait for up to 10ms for some new
+ * data before issuing a roundtrip. The roundtrip is necessary because the
+ * compositor may be queuing release events and we need to cause it to
+ * flush the queue */
+
+ if (wl_display_prepare_read_queue(dri2_dpy->wl_dpy,
+ dri2_dpy->wl_queue) != 0)
+ return wl_display_dispatch_queue_pending(dri2_dpy->wl_dpy,
+ dri2_dpy->wl_queue);
+
+ pollfd.fd = wl_display_get_fd(dri2_dpy->wl_dpy);
+ pollfd.events = POLLIN;
+ pollfd.revents = 0;
+
+ if (poll(&pollfd, 1, 10) < 0) {
+ wl_display_cancel_read(dri2_dpy->wl_dpy);
+ return -1;
+ }
+
+ if (pollfd.revents) {
+ if (wl_display_read_events(dri2_dpy->wl_dpy) < 0)
+ return -1;
+
+ return wl_display_dispatch_queue_pending(dri2_dpy->wl_dpy,
+ dri2_dpy->wl_queue);
+ } else {
+ wl_display_cancel_read(dri2_dpy->wl_dpy);
+ return roundtrip(dri2_dpy);
+ }
+}
+
+static int
get_back_bo(struct dri2_egl_surface *dri2_surf)
{
struct dri2_egl_display *dri2_dpy =
dri2_egl_display(dri2_surf->base.Resource.Display);
int i;
- if (dri2_surf->frame_callback == NULL) {
+ 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 {
- /* We throttle to the frame callback here so that we can be sure to have
- * received any release events before trying to decide whether to
- * allocate a new buffer */
+ /* We always want to throttle to some event (either a frame callback or
+ * a sync request) after the commit so that we can be sure the
+ * compositor has had a chance to handle it and send us a release event
+ * before we look for a free buffer */
do {
if (wl_display_dispatch_queue(dri2_dpy->wl_dpy,
dri2_dpy->wl_queue) == -1)
return EGL_FALSE;
- } while (dri2_surf->frame_callback != NULL);
+ } while (dri2_surf->throttle_callback != NULL);
}
if (dri2_surf->back == NULL) {
- for (i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
- /* Get an unlocked buffer, preferrably one with a dri_buffer already
- * allocated. */
- if (dri2_surf->color_buffers[i].locked)
- continue;
- if (dri2_surf->back == NULL)
- dri2_surf->back = &dri2_surf->color_buffers[i];
- else if (dri2_surf->back->dri_image == NULL)
- dri2_surf->back = &dri2_surf->color_buffers[i];
+ while (1) {
+ for (i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
+ /* Get an unlocked buffer, preferrably one with a dri_buffer
+ * already allocated. */
+ if (dri2_surf->color_buffers[i].locked)
+ continue;
+ if (dri2_surf->back == NULL)
+ dri2_surf->back = &dri2_surf->color_buffers[i];
+ else if (dri2_surf->back->dri_image == NULL)
+ dri2_surf->back = &dri2_surf->color_buffers[i];
+ }
+
+ if (dri2_surf->back != NULL)
+ break;
+
+ /* If we make it here then here then all of the buffers are locked.
+ * In theory this shouldn't happen because the compositor shouldn't
+ * be holding on to so many buffers. As a last resort we will poll
+ * the compositor at regular intervals in order to ensure we
+ * eventually get a buffer */
+
+ poll_compositor(dri2_dpy);
}
}
- if (dri2_surf->back == NULL)
- return -1;
if (dri2_surf->back->dri_image == NULL) {
dri2_surf->back->dri_image =
dri2_dpy->image->createImage(dri2_dpy->dri_screen,
@@ -497,16 +564,18 @@ static const __DRIimageLoaderExtension image_loader_extension = {
};
static void
-wayland_frame_callback(void *data, struct wl_callback *callback, uint32_t time)
+wayland_throttle_callback(void *data,
+ struct wl_callback *callback,
+ uint32_t time)
{
struct dri2_egl_surface *dri2_surf = data;
- dri2_surf->frame_callback = NULL;
+ dri2_surf->throttle_callback = NULL;
wl_callback_destroy(callback);
}
-static const struct wl_callback_listener frame_listener = {
- wayland_frame_callback
+static const struct wl_callback_listener throttle_listener = {
+ wayland_throttle_callback
};
static void
@@ -581,11 +650,14 @@ dri2_swap_buffers_with_damage(_EGLDriver *drv,
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->throttle_callback =
+ wl_surface_frame(dri2_surf->wl_win->surface);
+ 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_surf->back->age = 1;
dri2_surf->current = dri2_surf->back;
@@ -618,6 +690,18 @@ dri2_swap_buffers_with_damage(_EGLDriver *drv,
wl_surface_commit(dri2_surf->wl_win->surface);
+ /* If we're not waiting for a frame callback then we'll at least throttle
+ * to a sync callback so that we always give a chance for the compositor to
+ * handle the commit and send a release event before checking for a free
+ * buffer */
+ if (dri2_surf->throttle_callback == NULL) {
+ 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);
@@ -787,6 +871,60 @@ 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)
{
@@ -803,6 +941,7 @@ 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;
@@ -861,9 +1000,13 @@ dri2_initialize_wayland(_EGLDriver *drv, _EGLDisplay *disp)
dri2_dpy->extensions[3] = &use_invalidate.base;
dri2_dpy->extensions[4] = 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 c56a413..413518e 100644
--- a/src/egl/drivers/dri2/platform_x11.c
+++ b/src/egl/drivers/dri2/platform_x11.c
@@ -41,12 +41,6 @@
#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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