From b7b5ee593118f9dc884fc21237f51b9f599cc432 Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Wed, 11 Mar 2015 10:23:08 -0400 Subject: [PATCH] drm/fb: document drm_fb_helper_surface_size There has been some confusion about this struct. Lack of documentation probably didn't help. Signed-off-by: Rob Clark Reviewed-by: Alex Deucher Acked-by: Laurent Pinchart Signed-off-by: Daniel Vetter --- include/drm/drm_fb_helper.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index 21b944c456f6..0dfd94def593 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -44,6 +44,25 @@ struct drm_fb_helper_crtc { int x, y; }; +/** + * struct drm_fb_helper_surface_size - describes fbdev size and scanout surface size + * @fb_width: fbdev width + * @fb_height: fbdev height + * @surface_width: scanout buffer width + * @surface_height: scanout buffer height + * @surface_bpp: scanout buffer bpp + * @surface_depth: scanout buffer depth + * + * Note that the scanout surface width/height may be larger than the fbdev + * width/height. In case of multiple displays, the scanout surface is sized + * according to the largest width/height (so it is large enough for all CRTCs + * to scanout). But the fbdev width/height is sized to the minimum width/ + * height of all the displays. This ensures that fbcon fits on the smallest + * of the attached displays. + * + * So what is passed to drm_fb_helper_fill_var() should be fb_width/fb_height, + * rather than the surface size. + */ struct drm_fb_helper_surface_size { u32 fb_width; u32 fb_height; -- 2.20.1