[Mesa-dev] [PATCH] wayland/egl: Resize EGL surface on update buffer for swrast

[Olivier Fourdan]

Hi

On Thu, Oct 25, 2018 at 5:51 PM Juan A. Suarez Romero
<jasuarez at igalia.com> wrote:
>
> On Thu, 2018-10-25 at 14:48 +0200, Olivier Fourdan wrote:
> > After commit a9fb331ea ("wayland/egl: update surface size on window
> > resize"), the surface size is updated as soon as the resize is done, and
> > `update_buffers()` would resize only if the surface size differs from
> > the attached size.
> >
> > However, in the case of swrast, there is no resize callback and the
> > attached size is updated in `dri2_wl_swrast_commit_backbuffer()` prior
> > to the `swrast_update_buffers()` so the attached size is always up to
> > date when it reaches `swrast_update_buffers()` and the surface is never
> > resized.
> >
> > This can be observed with "totem" using the GDK backend on Wayland (the
> > default) when running on software rendering:
> >
> >   $ LIBGL_ALWAYS_SOFTWARE=true CLUTTER_BACKEND=gdk totem
> >
> > Resizing the window would leave the EGL surface size unchanged.
> >
> > To avoid the issue, partially revert the part of commit a9fb331ea for
> > `swrast_update_buffers()` and resize on the win size and not the
> > attached size.
> >
> > Fixes: a9fb331ea - wayland/egl: update surface size on window resize
> > Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
> > CC: Daniel Stone <daniel at fooishbar.org>
> > CC: Juan A. Suarez Romero <jasuarez at igalia.com>
> > CC: mesa-stable at lists.freedesktop.org
> > ---
>
> I've been checking why this happened. Turns out that in the original patch, we
> update the size in the resize_callback(), so we need to do the changes in
> update_buffers() accordingly.
>
> But turns out that with swrast we are not invoking resize_callback(), so we need
> to keep the old code in swrast_update_buffers().

Yeap, that's what I tried to explain in the commit message.

> Thanks for finding this.
>
> Reviewed-by: Juan A. Suarez <jasuarez at igalia.com>

Thanks Juan!

Could someone with commit access push that for me? Would be great to
have it fixed in the stable and forthcoming 18.3 branches as well.

>
> >  Resending because I got the "mesa-dev" address wrong! And a reply to the
> >  previous email won't fly with patchwork... Sorry!
> >
> >  src/egl/drivers/dri2/platform_wayland.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/egl/drivers/dri2/platform_wayland.c b/src/egl/drivers/dri2/platform_wayland.c
> > index 03a3e0993b..69a51e64fd 100644
> > --- a/src/egl/drivers/dri2/platform_wayland.c
> > +++ b/src/egl/drivers/dri2/platform_wayland.c
> > @@ -1652,8 +1652,8 @@ swrast_update_buffers(struct dri2_egl_surface *dri2_surf)
> >     if (dri2_surf->back)
> >        return 0;
> >
> > -   if (dri2_surf->base.Width != dri2_surf->wl_win->attached_width ||
> > -       dri2_surf->base.Height != dri2_surf->wl_win->attached_height) {
> > +   if (dri2_surf->base.Width != dri2_surf->wl_win->width ||
> > +       dri2_surf->base.Height != dri2_surf->wl_win->height) {
> >
> >        dri2_wl_release_buffers(dri2_surf);
> >
>

Cheers,
Olivier