[PATCH weston 2/2] compositor-drm: the cursor plane only supports ARGB

[Pekka Paalanen]

On Thu,  3 Dec 2015 14:07:12 -0600
Derek Foreman <derekf at osg.samsung.com> wrote:

> Keep XRGB apps out of the cursor plane, only ARGB is supported.
> 
> This prevents programs like weston-simple-shm from landing in the cursor
> plane and being misrendered.
> 
> Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
> ---
>  src/compositor-drm.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/src/compositor-drm.c b/src/compositor-drm.c
> index a6db933..84105e1 100644
> --- a/src/compositor-drm.c
> +++ b/src/compositor-drm.c
> @@ -1094,6 +1094,7 @@ drm_output_prepare_cursor_view(struct drm_output *output,
>  	struct drm_backend *b =
>  		(struct drm_backend *)output->base.compositor->backend;
>  	struct weston_buffer_viewport *viewport = &ev->surface->buffer_viewport;
> +	struct wl_shm_buffer *shmbuf;
>  
>  	if (ev->transform.enabled &&
>  	    (ev->transform.matrix.type > WESTON_MATRIX_TRANSFORM_TRANSLATE))
> @@ -1112,9 +1113,14 @@ drm_output_prepare_cursor_view(struct drm_output *output,
>  		return NULL;
>  	if (ev->geometry.scissor_enabled)
>  		return NULL;
> -	if (ev->surface->buffer_ref.buffer == NULL ||
> -	    !wl_shm_buffer_get(ev->surface->buffer_ref.buffer->resource) ||
> -	    ev->surface->width > b->cursor_width ||
> +	if (ev->surface->buffer_ref.buffer == NULL)
> +		return NULL;
> +	shmbuf = wl_shm_buffer_get(ev->surface->buffer_ref.buffer->resource);
> +	if (!shmbuf)
> +		return NULL;
> +	if (wl_shm_buffer_get_format(shmbuf) != WL_SHM_FORMAT_ARGB8888)
> +		return NULL;
> +	if (ev->surface->width > b->cursor_width ||
>  	    ev->surface->height > b->cursor_height)
>  		return NULL;
>  

Reviewed-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>

Also tested on intel SNB.

This will also prevent RGB565 surfaces going to the cursor plane, and
cursor_bo_update() would just screw that up totally because it has a
hardcoded "ev->surface->width * 4" in memcpy().

Not to mention that using surface dimensions for buffer access is...
not good. drm_output_prepare_cursor_view() is accounting for
buffer/output_scale and scissor, but it's missing viewport. It's also
not checking buffer_transform. So if someone happened to use
wl_viewport or buffer_transform on a small shm surface, we'd get funny
stuff. But that's another matter, just noticed it while reviewing.


Thanks,
pq
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