[PATCH 2/3] drm: validate possible_crtcs for primary and cursor planes

[Daniel Vetter]

On Thu, Dec 10, 2020 at 03:50:31PM +0000, Simon Ser wrote:
> If a primary or cursor plane is not compatible with a CRTC it's attached
> to via the legacy primary/cursor field, things will be broken for legacy
> user-space.
> 
> Signed-off-by: Simon Ser <contact at emersion.fr>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Pekka Paalanen <ppaalanen at gmail.com>

Yup, that's something we can validate.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> ---
>  drivers/gpu/drm/drm_mode_config.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index f1affc1bb679..2c73a60e8765 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -625,6 +625,7 @@ static void validate_encoder_possible_crtcs(struct drm_encoder *encoder)
>  void drm_mode_config_validate(struct drm_device *dev)
>  {
>  	struct drm_encoder *encoder;
> +	struct drm_crtc *crtc;
>  
>  	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>  		return;
> @@ -636,4 +637,19 @@ void drm_mode_config_validate(struct drm_device *dev)
>  		validate_encoder_possible_clones(encoder);
>  		validate_encoder_possible_crtcs(encoder);
>  	}
> +
> +	drm_for_each_crtc(crtc, dev) {
> +		if (crtc->primary) {
> +			WARN(!(crtc->primary->possible_crtcs & BIT(crtc->index)),
> +			     "Bogus primary plane possible_crtcs: [PLANE:%d:%s] must be compatible with [CRTC:%d:%s]\n",
> +			     crtc->primary->base.id, crtc->primary->name,
> +			     crtc->base.id, crtc->name);
> +		}
> +		if (crtc->cursor) {
> +			WARN(!(crtc->cursor->possible_crtcs & BIT(crtc->index)),
> +			     "Bogus cursor plane possible_crtcs: [PLANE:%d:%s] must be compatible with [CRTC:%d:%s]\n",
> +			     crtc->cursor->base.id, crtc->cursor->name,
> +			     crtc->base.id, crtc->name);
> +		}
> +	}
>  }
> -- 
> 2.29.2
> 
> 

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