[PATCH 1/2] wayland: Add support for eglSwapInterval
Pekka Paalanen
ppaalanen at gmail.com
Fri Sep 13 03:48:03 PDT 2013
On Wed, 11 Sep 2013 22:29:13 +0200
Axel Davy <davy at clipper.ens.fr> wrote:
> 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.
We had a lengthy discussion in IRC about that, and came to the idea
that we might need the maximum to be actually 5, not 4.
The +1 comes from sub-surfaces, and *might* happen when you have a
swapinterval=0 EGL rendering on a sub-surface in a busy-loop in a
thread, the sub-surface is in synchronized mode, parent surface gets
committed only occasionally, and the sub-surface ends up in an hardware
overlay plane. Sheesh...
If we really want to guarantee maximal framerate on the sub-surface
whose display is throttled not only by the compositor, but other parts
of the client too...
Thanks,
pq
> 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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