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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2019-12-04 13:00:11 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2019-12-10 23:44:02 +0300 |
| commit | 0380c6846a4be705b2d5c964b01ba1e5aaa3f5df (patch) | |
| tree | 13cb9637c78c33a4802da82ac8afb5d5de2946d0 /Documentation/gpu | |
| parent | 3cc1430cdbca12044571e3849cd57ac2e0d695c1 (diff) | |
| download | linux-0380c6846a4be705b2d5c964b01ba1e5aaa3f5df.tar.xz | |
drm/atomic: Update docs around locking and commit sequencing
Both locking and especially sequencing of nonblocking commits have
evolved a lot. The details are all there, but I noticed that the big
picture and connections have fallen behind a bit. Apply polish.
Motivated by some review discussions with Thierry.
v2: Review from Thierry
Reviewed-by: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191204100011.859468-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/drm-kms.rst | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index c68588ce4090..b9330343d1bc 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -260,7 +260,8 @@ Taken all together there's two consequences for the atomic design: drm_connector_state <drm_connector_state>` for connectors. These are the only objects with userspace-visible and settable state. For internal state drivers can subclass these structures through embeddeding, or add entirely new state - structures for their globally shared hardware functions. + structures for their globally shared hardware functions, see :c:type:`struct + drm_private_state<drm_private_state>`. - An atomic update is assembled and validated as an entirely free-standing pile of structures within the :c:type:`drm_atomic_state <drm_atomic_state>` @@ -269,6 +270,14 @@ Taken all together there's two consequences for the atomic design: to the driver and modeset objects. This way rolling back an update boils down to releasing memory and unreferencing objects like framebuffers. +Locking of atomic state structures is internally using :c:type:`struct +drm_modeset_lock <drm_modeset_lock>`. As a general rule the locking shouldn't be +exposed to drivers, instead the right locks should be automatically acquired by +any function that duplicates or peeks into a state, like e.g. +:c:func:`drm_atomic_get_crtc_state()`. Locking only protects the software data +structure, ordering of committing state changes to hardware is sequenced using +:c:type:`struct drm_crtc_commit <drm_crtc_commit>`. + Read on in this chapter, and also in :ref:`drm_atomic_helper` for more detailed coverage of specific topics. |