drm: Global atomic state handling

Some differences compared to Rob's patches again:
- Dropped the committed and checked booleans. Checking will be
  internally enforced by always calling ->atomic_check before
  ->atomic_commit. And async handling needs to be solved differently
  because the current scheme completely side-steps ww mutex deadlock
  avoidance (and so either reinvents a new deadlock avoidance wheel or
  like the current code just deadlocks).

- State for connectors needed to be added, since now they have a
  full-blown drm_connector_state (so that drivers have something to
  attach their own stuff to).

- Refcounting is gone. I plane to solve async updates differently,
  since the lock-passing scheme doesn't cut it (since it abuses ww
  mutexes). Essentially what we need for async is a simple ownership
  transfer from the caller to the driver. That doesn't need full-blown
  refcounting.

- The acquire ctx is a pointer. Real atomic callers should have that
  on their stack, legacy entry points need to put the right one
  (obtained by drm_modeset_legacy_acuire_ctx) in there.

- I've dropped all hooks except check/commit. All the begin/end
  handling is done by core functions and is the same.

- commit/check are just thin wrappers that ensure that ->check is
  always called.

- To help out with locking in the legacy implementations I've added a
  helper to just grab all locks in the backoff case.

v2: Add notices that check/commit can fail with EDEADLK.

v3:
- More consistent naming for state_alloc.
- Add state_clear which is needed for backoff and retry.

v4: Planes/connectors can switch between crtcs, and we need to be
careful that we grab the state (and locks) for both the old and new
crtc. Improve the interface functions to ensure this.

v5: Add functions to grab affected connectors for a crtc and to recompute
the crtc->enable state. This is useful for both helper and atomic ioctl
code when e.g. removing a connector.

v6: Squash in fixup from Fengguang to use ERR_CAST.

v7: Add debug output.

v8: Make checkpatch happy about kcalloc argument ordering.

v9: Improve kerneldoc in drm_crtc.h

v10:
- Fix another kcalloc argument misorder I've missed.
- More polish for kerneldoc.

v11: Clarify the ownership rules for the state object. The new rule is
that a successful drm_atomic_commit (whether synchronous or asnyc)
always inherits the state and is responsible for the clean-up. That
way async and sync ->commit functions are more similar.

v12: A few bugfixes:
- Assign state->state pointers correctly when grabbing state objects -
  we need to link them up with the global state.
- Handle a NULL crtc in set_crtc_for_plane to simplify code flow a bit
  for the callers of this function.

v13: Review from Sean:
- kerneldoc spelling fixes
- Don't overallocate states->planes.
- Handle NULL crtc in set_crtc_for_connector.

v14: Sprinkle __must_check over all functions which do wait/wound
locking to make sure callers don't forget this. Since I have ;-)

v15: Be more explicit in the kerneldoc when functions can return
-EDEADLK what to do. And that every other -errno is fatal.

v16: Indent with tabs instead of space, spotted by Ander.

v17: Review from Thierry, small kerneldoc and other naming polish.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 65 insertions, 0 deletions

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
new file mode 100644
index 000000000000..5bb15f550c42
--- /dev/null
+++ b/include/drm/drm_atomic.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2014 Red Hat
+ * Copyright (C) 2014 Intel Corp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ * Rob Clark <robdclark@gmail.com>
+ * Daniel Vetter <daniel.vetter@ffwll.ch>
+ */
+
+#ifndef DRM_ATOMIC_H_
+#define DRM_ATOMIC_H_
+
+struct drm_atomic_state * __must_check
+drm_atomic_state_alloc(struct drm_device *dev);
+void drm_atomic_state_clear(struct drm_atomic_state *state);
+void drm_atomic_state_free(struct drm_atomic_state *state);
+
+struct drm_crtc_state * __must_check
+drm_atomic_get_crtc_state(struct drm_atomic_state *state,
+			  struct drm_crtc *crtc);
+struct drm_plane_state * __must_check
+drm_atomic_get_plane_state(struct drm_atomic_state *state,
+			   struct drm_plane *plane);
+struct drm_connector_state * __must_check
+drm_atomic_get_connector_state(struct drm_atomic_state *state,
+			       struct drm_connector *connector);
+
+int __must_check
+drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state,
+			      struct drm_crtc *crtc);
+int __must_check
+drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
+				  struct drm_crtc *crtc);
+int __must_check
+drm_atomic_add_affected_connectors(struct drm_atomic_state *state,
+				   struct drm_crtc *crtc);
+int
+drm_atomic_connectors_for_crtc(struct drm_atomic_state *state,
+			       struct drm_crtc *crtc);
+
+void drm_atomic_legacy_backoff(struct drm_atomic_state *state);
+
+int __must_check drm_atomic_check_only(struct drm_atomic_state *state);
+int __must_check drm_atomic_commit(struct drm_atomic_state *state);
+int __must_check drm_atomic_async_commit(struct drm_atomic_state *state);
+
+#endif /* DRM_ATOMIC_H_ */