[PATCH] drm: mxsfb: fix fence synchronization

[Lucas Stach]

On Fr, 2020-11-20 at 22:13 +0100, Lucas Stach wrote:
> The conversion away from the simple display pipeline helper missed
> to convert the prepare_fb plane callback, so no fences are attached to
> the atomic state, breaking synchronization with other devices. Fix
> this by plugging in the drm_gem_fb_prepare_fb helper function.

This is a regression in the 5.10 release series, so I would appreciate
if someone could review/ack this patch so I can smash it into
drm-misc-fixes.

Regards,
Lucas

> Fixes: ae1ed009328 (drm: mxsfb: Stop using DRM simple display pipeline helper)
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  drivers/gpu/drm/mxsfb/mxsfb_kms.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> index b721b8b262ce..4d556532281a 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> @@ -22,6 +22,7 @@
>  #include <drm/drm_fb_cma_helper.h>
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
>  #include <drm/drm_plane.h>
>  #include <drm/drm_plane_helper.h>
>  #include <drm/drm_vblank.h>
> @@ -485,11 +486,13 @@ static void mxsfb_plane_overlay_atomic_update(struct drm_plane *plane,
>  }
>  
>  static const struct drm_plane_helper_funcs mxsfb_plane_primary_helper_funcs = {
> +	.prepare_fb = drm_gem_fb_prepare_fb,
>  	.atomic_check = mxsfb_plane_atomic_check,
>  	.atomic_update = mxsfb_plane_primary_atomic_update,
>  };
>  
>  static const struct drm_plane_helper_funcs mxsfb_plane_overlay_helper_funcs = {
> +	.prepare_fb = drm_gem_fb_prepare_fb,
>  	.atomic_check = mxsfb_plane_atomic_check,
>  	.atomic_update = mxsfb_plane_overlay_atomic_update,
>  };