[PATCH 1/2] wayland: Add support for eglSwapInterval
Axel Davy
davy at clipper.ens.fr
Wed Sep 11 13:29:13 PDT 2013
I think you should too set the number of back buffers to 4 instead of 3.
It looks like if the compositor wants to use the buffers as framebuffers
and do a pageflip,
it uses 2 buffers at a time (one used for the frame displayed, and one
used for the pending pageFlip request). The third buffer sent is not
released and waits for the next frame. If there is only 3 buffers, the
client will be without free buffers and blocked in eglSwapBuffers.
I may be wrong, but I think the number of back buffers should be set to 4.
Axel Davy
Le 11/09/2013 20:28, Neil Roberts a écrit :
> 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 it simply doesn't
> install a frame callback so that the next time eglSwapBuffers is called it
> won't delay.
>
> The second change is that in get_back_bo instead of returning with an error if
> all three buffers are locked it will now block in a dispatch loop so that it
> can receive the buffer release events. The assumption is that the compositor
> is unlikely to lock all three buffers so if we find that all the buffers are
> locked then we are probably just rendering faster than we are processing the
> release events. Therefore the release events should be available very early.
>
> 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 | 6 ++
> src/egl/drivers/dri2/platform_wayland.c | 121 ++++++++++++++++++++++++++------
> src/egl/drivers/dri2/platform_x11.c | 6 --
> 3 files changed, 107 insertions(+), 26 deletions(-)
>
> diff --git a/src/egl/drivers/dri2/egl_dri2.h b/src/egl/drivers/dri2/egl_dri2.h
> index fba5f81..849927b 100644
> --- a/src/egl/drivers/dri2/egl_dri2.h
> +++ b/src/egl/drivers/dri2/egl_dri2.h
> @@ -221,6 +221,12 @@ 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..83e7aab 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;
> }
>
> /**
> @@ -261,24 +269,36 @@ 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->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];
> + /* 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);
> +
> + 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)
> + break;
> +
> + /* If we make it here then here then all of the buffers are locked.
> + * It wouldn't make sense for the compositor to keep all three
> + * buffers so it must mean that we are rendering too fast without
> + * getting a chance to see the release events. Therefore we can just
> + * block for the release event here */
> + if (wl_display_dispatch_queue(dri2_dpy->wl_dpy,
> + dri2_dpy->wl_queue) < 0)
> + return -1;
> }
> }
>
> - 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,
> @@ -511,11 +531,13 @@ 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)
> @@ -802,6 +824,60 @@ 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 +893,7 @@ 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 +953,13 @@ 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,
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