path: root/Documentation/gpu
diff options
authorThomas Zimmermann <>2021-02-08 12:55:34 +0100
committerThomas Zimmermann <>2021-02-08 13:00:14 +0100
commit6dd7b6ce43acd70f75ae285fee8eeb2dd4933dce (patch)
tree6232501cad483644006436c738f5aa293cb8ab63 /Documentation/gpu
parentdb0c6bd2c0c0dada8927cd46a7c34c316a3a6c04 (diff)
drm: Add additional atomic helpers for shadow-buffered planes
Several drivers use GEM buffer objects as shadow buffers for the actual framebuffer memory. Right now, drivers do these vmap operations in their commit tail, which is actually not allowed by the locking rules for the dma-buf reservation lock. The involved BO has to be vmapped in the plane's prepare_fb callback and vunmapped in cleanup_fb. This patch introduces atomic helpers for such shadow planes. Plane functions manage the plane state for shadow planes. The provided implementations for prepare_fb and cleanup_fb vmap and vunmap all BOs of struct drm_plane_state.fb. The mappings are afterwards available in the plane's commit-tail functions. For now, all rsp drivers use the simple KMS helpers, so we add the plane callbacks and wrappers for simple KMS. The internal plane functions can later be exported as needed. v3: * documentation fixes v2: * make duplicate_state interface compatible with struct drm_plane_funcs Signed-off-by: Thomas Zimmermann <> Tested-by: Gerd Hoffmann <> Acked-by: Gerd Hoffmann <> Link:
Diffstat (limited to 'Documentation/gpu')
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index b89ddd06dabb..389892f36185 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -80,6 +80,18 @@ Atomic State Helper Reference
.. kernel-doc:: drivers/gpu/drm/drm_atomic_state_helper.c
+GEM Atomic Helper Reference
+.. kernel-doc:: drivers/gpu/drm/drm_gem_atomic_helper.c
+ :doc: overview
+.. kernel-doc:: include/drm/drm_gem_atomic_helper.h
+ :internal:
+.. kernel-doc:: drivers/gpu/drm/drm_gem_atomic_helper.c
+ :export:
Simple KMS Helper Reference