On Wed, Mar 21, 2018 at 04:28:58PM +0100, Paul Kocialkowski wrote:
> In order to check whether the backend supports a specific format, an
> explicit list and a related helper are introduced.
>
> They are then used to determine whether the frontend should be used for
> a layer, when the format is not supported by the backend.
>
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/sun4i/sun4i_backend.c | 48 ++++++++++++++++++++++++++++++++++-
> drivers/gpu/drm/sun4i/sun4i_backend.h | 1 +
> 2 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index 274a1db6fa8e..7703ba989743 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -172,6 +172,39 @@ static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
> return 0;
> }
>
> +static const uint32_t sun4i_backend_formats[] = {
> + /* RGB */
> + DRM_FORMAT_ARGB4444,
> + DRM_FORMAT_RGBA4444,
> + DRM_FORMAT_ARGB1555,
> + DRM_FORMAT_RGBA5551,
> + DRM_FORMAT_RGB565,
> + DRM_FORMAT_RGB888,
> + DRM_FORMAT_XRGB8888,
> + DRM_FORMAT_BGRX8888,
> + DRM_FORMAT_ARGB8888,
> + /* YUV422 */
> + DRM_FORMAT_YUYV,
> + DRM_FORMAT_YVYU,
> + DRM_FORMAT_UYVY,
> + DRM_FORMAT_VYUY,
Ordering them by alphabetical order would be better.
> +};
> +
> +bool sun4i_backend_format_is_supported(uint32_t fmt)
> +{
> + bool found = false;
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++) {
> + if (sun4i_backend_formats[i] == fmt) {
> + found = true;
> + break;
return true?
> + }
> + }
> +
> + return found;
> +}
> +
> int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
> int layer, struct drm_plane *plane)
> {
> @@ -436,15 +469,28 @@ static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
> {
> struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
> struct sun4i_backend *backend = layer->backend;
> + struct drm_framebuffer *fb = state->fb;
>
> if (IS_ERR(backend->frontend))
> return false;
>
> + /*
> + * Let's pretend that every format is either supported by the backend or
> + * the frontend. This is not true in practice, as some tiling modes are
> + * not supported by either. There is still room to check this later in
> + * the atomic check process.
Then I guess there these tiling modes will not be exposed and we won't
ever get that far, wouldn't we?
> + */
> + if (!sun4i_backend_format_is_supported(fb->format->format))
> + return true;
Even though there's a comment, this is not really natural. We are
checking whether the frontend supports the current plane_state, so it
just makes more sense to check whether the frontend supports the
format, rather than if the backend doesn't support them.
Maxime
--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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