[Mesa-dev] [PATCH 13/13] wayland: Add buffer handling and visuals for fp16 formats

[Strasser, Kevin]

Daniel Stone wrote:
> On Mon, 28 Jan 2019 at 18:43, Kevin Strasser <kevin.strasser at intel.com> wrote:
> > Set loader caps indicating that wayland can handle both rgba ordering and
> > fp16 formats.
> >
> > NOTE: This requries libwayland to provide definitions for
> > WL_SHM_FORMAT_XBGR16161616F and WL_SHM_FORMAT_ABGR16161616F
>
> To be honest, we wouldn't be very likely to add those until at least
> Pixman got support for FP16 formats.

Good to know, I saw that fp32 was added to pixman recently. Maybe fp16
conversions could be added soon. I don't mind dropping this patch from the
series for now.

> (Can you also upload those through, e.g., TexImage2D when using GLES?)

You can upload half float pixels through TexImage2D, yes. That's probably not
what you were asking...

> > static const __DRIimageLoaderExtension image_loader_extension = {
> > diff --git a/src/egl/wayland/wayland-drm/wayland-drm.c
> > b/src/egl/wayland/wayland-drm/wayland-drm.c
> > index 3c6696d..9dd7fd3 100644
> > --- a/src/egl/wayland/wayland-drm/wayland-drm.c
> > +++ b/src/egl/wayland/wayland-drm/wayland-drm.c
> > @@ -117,6 +117,8 @@ drm_create_buffer(struct wl_client *client, struct
> > wl_resource *resource,
> >          case WL_DRM_FORMAT_XRGB8888:
> >          case WL_DRM_FORMAT_YUYV:
> >          case WL_DRM_FORMAT_RGB565:
> > +        case WL_DRM_FORMAT_ABGR16161616F:
> > +        case WL_DRM_FORMAT_XBGR16161616F:
> >                  break;
> >          default:
> >                  wl_resource_post_error(resource,
> > @@ -220,6 +222,10 @@ bind_drm(struct wl_client *client, void *data, uint32_t
> > version, uint32_t id)
> >                                WL_DRM_FORMAT_XRGB8888);
> >          wl_resource_post_event(resource, WL_DRM_FORMAT,
> >                                 WL_DRM_FORMAT_RGB565);
> > +        wl_resource_post_event(resource, WL_DRM_FORMAT,
> > +                               WL_DRM_FORMAT_ABGR16161616F);
> > +        wl_resource_post_event(resource, WL_DRM_FORMAT,
> > +                               WL_DRM_FORMAT_XBGR16161616F);
>
> These should only be advertised if the underlying driver actually
> supports texturing from FP16.
>
> Regardless, we try to avoid adding ~anything new to wl_drm. It would
> be much better to have DRM FourCC definitions for these formats and
> use them via the linux_dmabuf extension if available.
>
> If the driver advertises DRM_FORMAT_*16161616F formats through the EGL
> dmabuf format query extension, then the server will automatically
> advertise them to clients and import will just work on the server side
> without having to touch src/egl/wayland/wayland-drm/, which we'd
> mostly prefer to be preserved in amber.

Understood, I'll drop this part of the patch.

Thanks,
Kevin