[PATCH 3/4] drm/vkms: Add atomic_helper_check_plane_state

[Daniel Vetter]

On Mon, Jul 09, 2018 at 06:47:34PM +0300, Haneen Mohammed wrote:
> Call atomic_helper_check_plane_state to clip plane coordinates.
> 
> Signed-off-by: Haneen Mohammed <hamohammed.sa at gmail.com>
> ---
>  drivers/gpu/drm/vkms/vkms_plane.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index f464eb0e05dd..bf37aebac0fb 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -7,9 +7,10 @@
>   */
>  
>  #include "vkms_drv.h"
> -#include <drm/drm_plane_helper.h>
> +#include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_plane_helper.h>
>  
>  static const struct drm_plane_funcs vkms_plane_funcs = {
>  	.update_plane		= drm_atomic_helper_update_plane,
> @@ -23,7 +24,20 @@ static const struct drm_plane_funcs vkms_plane_funcs = {
>  static int vkms_plane_atomic_check(struct drm_plane *plane,
>  				   struct drm_plane_state *state)
>  {
> -	return 0;
> +	struct drm_crtc_state *crtc_state;
> +
> +	if (!state->fb || !state->crtc)
> +		return 0;
> +
> +	crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
> +
> +	if (IS_ERR(crtc_state))
> +		return PTR_ERR(crtc_state);
> +
> +	return drm_atomic_helper_check_plane_state(state, crtc_state,
> +						   DRM_PLANE_HELPER_NO_SCALING,
> +						   DRM_PLANE_HELPER_NO_SCALING,
> +						   false, true);

So one additional thing we need to check here is plane_state->visible
(which is computed by the check_plane_state) function. For now we can't
handle a disabled primary plane (we'd need to change our crc function to
compute the crc of an all-black screen), hence need to reject this:
	ret = drm_atomic_helper_check_plane_state(state, crtc_state,
						   DRM_PLANE_HELPER_NO_SCALING,
						   DRM_PLANE_HELPER_NO_SCALING,
						   false, true);
	if (ret != 0)
		return ret;

	/* for now primary plane must be visible and full screen */
	if (!plane_state->visible)
		return -EINVAL;

	return 0;

otherwise lgtm.
-Daniel

>  }
>  
>  static void vkms_primary_plane_update(struct drm_plane *plane,
> -- 
> 2.17.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch