[Intel-gfx] [PATCH v3 6/7] drm: Validate encoder->possible_crtcs

[Daniel Vetter]

On Tue, Feb 11, 2020 at 06:22:07PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> WARN if the encoder possible_crtcs is effectively empty or contains
> bits for non-existing crtcs.
> 
> v2: Move to drm_mode_config_validate() (Daniel)
>     Make the docs say we WARN when this is wrong (Daniel)
>     Extract full_crtc_mask()
> 
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

When pushing the fixup needs to be applied before the validation patch
here, because we don't want to anger the bisect gods.

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

I think with the fixup we should be good enough with the existing nonsense
in drivers. Fingers crossed.
-Daniel


> ---
>  drivers/gpu/drm/drm_mode_config.c | 27 ++++++++++++++++++++++++++-
>  include/drm/drm_encoder.h         |  2 +-
>  2 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index afc91447293a..4c1b350ddb95 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -581,6 +581,29 @@ static void validate_encoder_possible_clones(struct drm_encoder *encoder)
>  	     encoder->possible_clones, encoder_mask);
>  }
>  
> +static u32 full_crtc_mask(struct drm_device *dev)
> +{
> +	struct drm_crtc *crtc;
> +	u32 crtc_mask = 0;
> +
> +	drm_for_each_crtc(crtc, dev)
> +		crtc_mask |= drm_crtc_mask(crtc);
> +
> +	return crtc_mask;
> +}
> +
> +static void validate_encoder_possible_crtcs(struct drm_encoder *encoder)
> +{
> +	u32 crtc_mask = full_crtc_mask(encoder->dev);
> +
> +	WARN((encoder->possible_crtcs & crtc_mask) == 0 ||
> +	     (encoder->possible_crtcs & ~crtc_mask) != 0,
> +	     "Bogus possible_crtcs: "
> +	     "[ENCODER:%d:%s] possible_crtcs=0x%x (full crtc mask=0x%x)\n",
> +	     encoder->base.id, encoder->name,
> +	     encoder->possible_crtcs, crtc_mask);
> +}
> +
>  void drm_mode_config_validate(struct drm_device *dev)
>  {
>  	struct drm_encoder *encoder;
> @@ -588,6 +611,8 @@ void drm_mode_config_validate(struct drm_device *dev)
>  	drm_for_each_encoder(encoder, dev)
>  		fixup_encoder_possible_clones(encoder);
>  
> -	drm_for_each_encoder(encoder, dev)
> +	drm_for_each_encoder(encoder, dev) {
>  		validate_encoder_possible_clones(encoder);
> +		validate_encoder_possible_crtcs(encoder);
> +	}
>  }
> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
> index 3741963b9587..b236269f41ac 100644
> --- a/include/drm/drm_encoder.h
> +++ b/include/drm/drm_encoder.h
> @@ -142,7 +142,7 @@ struct drm_encoder {
>  	 * the bits for all &drm_crtc objects this encoder can be connected to
>  	 * before calling drm_dev_register().
>  	 *
> -	 * In reality almost every driver gets this wrong.
> +	 * You will get a WARN if you get this wrong in the driver.
>  	 *
>  	 * Note that since CRTC objects can't be hotplugged the assigned indices
>  	 * are stable and hence known before registering all objects.
> -- 
> 2.24.1
> 

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