`Op 17-04-2019 om 13:01 schreef Maxime Ripard:> On Wed, Apr 17, 2019 at 12:47:48PM +0200, Maarten Lankhorst wrote:>>> +/**>>> + * drm_format_info_plane_width - width of the plane given the first plane>>> + * @format: pixel format info>>> + * @width: width of the first plane>>> + * @plane: plane index>>> + *>>> + * Returns:>>> + * The width of @plane, given that the width of the first plane is @width.>>> + */>>> +static inline>>> +int drm_format_info_plane_width(const struct drm_format_info *info, int width,>>> +				int plane)>>> +{>>> +	if (!info || plane >= info->num_planes)>>> +		return 0;>>> +>>> +	if (plane == 0)>>> +		return width;>>> +>>> +	return width / info->hsub;>>> +}>>> +>>> +/**>>> + * drm_format_info_plane_height - height of the plane given the first plane>>> + * @format: pixel format info>>> + * @height: height of the first plane>>> + * @plane: plane index>>> + *>>> + * Returns:>>> + * The height of @plane, given that the height of the first plane is @height.>>> + */>>> +static inline>>> +int drm_format_info_plane_height(const struct drm_format_info *info, int height,>>> +				 int plane)>>> +{>>> +	if (!info || plane >= info->num_planes)>>> +		return 0;>>> +>>> +	if (plane == 0)>>> +		return height;>>> +>>> +	return height / info->vsub;>>> +}>> Why the null checks? None of the other inlines for drm_format_info>> perform them.> Unless I'm mistaken, the subsampling only applies to the planes with> the chrominance, which are always >= 1. Therefore the plane 0 is> always the luminance, to which the subsampling doesn't apply.>> Or are you talking about something else?The info == NULL check. :)`