drm/docs: More links for implicit/explicit fencing.

drm_atomic_set_fence_for_plane() contains the main discussion from a
driver pov, link to that from more places.

Cc: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190603142848.26487-1-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 6fd48efe288cbee8c35a8e780a3d79ec694c21c0..6791245963c3556da88cfc70dc8340590887511b 100644 (file)
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -284,6 +284,9 @@ EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
  * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
  * gem based framebuffer drivers which have their buffers always pinned in
  * memory.
+ *
+ * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
+ * explicit fencing in atomic modeset updates.
  */
 int drm_gem_fb_prepare_fb(struct drm_plane *plane,
                          struct drm_plane_state *state)
@@ -314,6 +317,9 @@ EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
  * &dma_buf attached, extracts the exclusive fence and attaches it to plane
  * state for the atomic helper to wait on. Drivers can use this as their
  * &drm_simple_display_pipe_funcs.prepare_fb callback.
+ *
+ * See drm_atomic_set_fence_for_plane() for a discussion of implicit and
+ * explicit fencing in atomic modeset updates.
  */
 int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
                                              struct drm_plane_state *plane_state)

diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 6078c700d9ba547c6aba90d83df7bec4fa8bbb7e..cd5903ad33f7e379a9f8a5df5f9541e4bcdcc2f5 100644 (file)
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -69,7 +69,7 @@ struct drm_plane_state {
         *
         * Optional fence to wait for before scanning out @fb. The core atomic
         * code will set this when userspace is using explicit fencing. Do not
-        * write this directly for a driver's implicit fence, use
+        * write this field directly for a driver's implicit fence, use
         * drm_atomic_set_fence_for_plane() to ensure that an explicit fence is
         * preserved.
         *