[PATCH v5 5/9] drm: Handle aspect-ratio info in getblob

[Ville Syrjälä]

On Thu, Feb 15, 2018 at 05:50:58PM +0530, Nautiyal, Ankit K wrote:
> From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> 
> If the user space  does not support aspect-ratio, then getblob called
> with the blob id of a user mode, should clear the aspect ratio
> information in the blob data.
> 
> Currently for a given blob id, there is no way to determine if the
> blob stores user mode or not. This can only be ascertained when the
> blob is used for an atomic modeset call.
> 
> This patch:
> -adds a new field 'is_video_mode' in drm_property_blob to
>  differentiate between the video mode blobs and the other blobs.
> -sets the field 'is_video_mode' when the blob is used for modeset.
> -removes the aspect-ratio info from the mode data if aspect ratio is
>  not supported by the user, while returning the blob to the user, in
>  getblob ioctl.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/drm_atomic.c   | 1 +
>  drivers/gpu/drm/drm_property.c | 6 ++++++
>  include/drm/drm_property.h     | 2 ++
>  3 files changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 46733d5..86b483e 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -464,6 +464,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>  	else if (property == config->prop_mode_id) {
>  		struct drm_property_blob *mode =
>  			drm_property_lookup_blob(dev, val);
> +		mode->is_video_mode = true;
>  		ret = drm_atomic_set_mode_prop_for_crtc(state, mode);
>  		drm_property_blob_put(mode);
>  		return ret;
> diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c
> index bae50e6..639787c 100644
> --- a/drivers/gpu/drm/drm_property.c
> +++ b/drivers/gpu/drm/drm_property.c
> @@ -746,6 +746,12 @@ int drm_mode_getblob_ioctl(struct drm_device *dev,
>  	if (!blob)
>  		return -ENOENT;
>  
> +	if (blob->is_video_mode && !file_priv->aspect_ratio_allowed) {
> +		struct drm_mode_modeinfo *mode =
> +			(struct drm_mode_modeinfo *) blob->data;
> +		mode->flags &= (~DRM_MODE_FLAG_PIC_AR_MASK);

This is still clobbering the internal state. If another client with
the aspect ratio cap comes in later and asks for the same blob we 
can no longer tell it what the aspect ratio was. So I think we have
to make a temporary copy of the mode here.

Also pointless parens.

> +	}
> +
>  	if (out_resp->length == blob->length) {
>  		if (copy_to_user(u64_to_user_ptr(out_resp->data),
>  				 blob->data,
> diff --git a/include/drm/drm_property.h b/include/drm/drm_property.h
> index 8a522b4..95e6e32 100644
> --- a/include/drm/drm_property.h
> +++ b/include/drm/drm_property.h
> @@ -194,6 +194,7 @@ struct drm_property {
>   * @head_global: entry on the global blob list in
>   * 	&drm_mode_config.property_blob_list.
>   * @head_file: entry on the per-file blob list in &drm_file.blobs list.
> + * @is_video_mode: flag to mark the blobs that contain drm_mode_modeinfo.
>   * @length: size of the blob in bytes, invariant over the lifetime of the object
>   * @data: actual data, embedded at the end of this structure
>   *
> @@ -208,6 +209,7 @@ struct drm_property_blob {
>  	struct drm_device *dev;
>  	struct list_head head_global;
>  	struct list_head head_file;
> +	bool is_video_mode;
>  	size_t length;
>  	unsigned char data[];
>  };
> -- 
> 2.7.4

-- 
Ville Syrjälä
Intel OTC