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authorRob Clark <robdclark@gmail.com>2015-03-11 10:23:08 -0400
committerDaniel Vetter <daniel.vetter@ffwll.ch>2015-03-11 22:07:33 +0100
commitb7b5ee593118f9dc884fc21237f51b9f599cc432 (patch)
tree6e6304cbffa6c893c5250bb6d870cdd12aaf40e7
parent1d002fa720738bcd0bddb9178e9ea0773288e1dd (diff)
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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 <robdclark@gmail.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--include/drm/drm_fb_helper.h19
1 files changed, 19 insertions, 0 deletions
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;