So that bridge drivers have a way to check/reject an atomic operation.
The drm_atomic_bridge_chain_check() (which is just a wrapper around
the ->atomic_check() hook) is called in place of
drm_bridge_chain_mode_fixup() (when ->atomic_check() is not implemented,
the core falls back to ->mode_fixup(), so the behavior should stay
the same for existing bridge drivers).
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
Laurent,
I haven't clarified what's allowed to be changed in
->mode_fixup()/->atomic_check() simply because I don't know what the
constraints are. Since the problem already exists with the
->mode_fixup() hook, and given the goal of this series is to support
bus_format negotation (which does not involve tweaking the display
mode), I'd prefer to delay these semantic adjustments if you're okay
with that.
Regards,
Boris
Changes in v2:
* Clarify the fact that ->atomic_check() is replacing ->mode_fixup()
---
drivers/gpu/drm/drm_atomic_helper.c | 12 +++---
drivers/gpu/drm/drm_bridge.c | 62 +++++++++++++++++++++++++++++
include/drm/drm_bridge.h | 29 +++++++++++++-
3 files changed, 96 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index b3f59e757b30..2a4ac69ccc93 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -445,12 +445,12 @@ mode_fixup(struct drm_atomic_state *state)
encoder = new_conn_state->best_encoder;
funcs = encoder->helper_private;
- ret = drm_bridge_chain_mode_fixup(&encoder->bridge,
- &new_crtc_state->mode,
- &new_crtc_state->adjusted_mode);
- if (!ret) {
- DRM_DEBUG_ATOMIC("Bridge fixup failed\n");
- return -EINVAL;
+ ret = drm_atomic_bridge_chain_check(&encoder->bridge,
+ new_crtc_state,
+ new_conn_state);
+ if (ret) {
+ DRM_DEBUG_ATOMIC("Bridge atomic check failed\n");
+ return ret;
}
if (funcs && funcs->atomic_check) {
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 5c83cac7975e..7f7e0ea5b06c 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -581,6 +581,68 @@ void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
+static int drm_atomic_bridge_check(struct drm_bridge *bridge,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state)
+{
+ if (bridge->funcs->atomic_check) {
+ struct drm_bridge_state *bridge_state;
+ int ret;
+
+ bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
+ bridge);
+ if (WARN_ON(!bridge_state))
+ return -EINVAL;
+
+ ret = bridge->funcs->atomic_check(bridge, bridge_state,
+ crtc_state, conn_state);
+ if (ret)
+ return ret;
+ } else if (bridge->funcs->mode_fixup) {
+ if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode,
+ &crtc_state->adjusted_mode))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
+ * @bridge: bridge control structure
+ * @crtc_state: new CRTC state
+ * @conn_state: new connector state
+ *
+ * Calls &drm_bridge_funcs.atomic_check() (falls back on
+ * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain,
+ * starting from the last bridge to the first. These are called before calling
+ * &drm_encoder_helper_funcs.atomic_check()
+ *
+ * RETURNS:
+ * 0 on success, a negative error code on failure
+ */
+int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state)
+{
+ struct drm_encoder *encoder = bridge->encoder;
+ struct drm_bridge *iter;
+
+ list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
+ int ret;
+
+ ret = drm_atomic_bridge_check(iter, crtc_state, conn_state);
+ if (ret)
+ return ret;
+
+ if (iter == bridge)
+ break;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_atomic_bridge_chain_check);
+
/**
* drm_atomic_helper_bridge_destroy_state() - Default destroy state helper
* @bridge: the bridge this state refers to
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 231f62cd681d..7fdce6dc5f26 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -126,7 +126,9 @@ struct drm_bridge_funcs {
* this function passes all other callbacks must succeed for this
* configuration.
*
- * The mode_fixup callback is optional.
+ * The mode_fixup callback is optional. &drm_bridge_funcs.mode_fixup()
+ * is not called when &drm_bridge_funcs.atomic_check() is implemented,
+ * so only one of them should be provided.
*
* NOTE:
*
@@ -389,6 +391,28 @@ struct drm_bridge_funcs {
void (*atomic_destroy_state)(struct drm_bridge *bridge,
struct drm_bridge_state *state);
+ /**
+ * @atomic_check:
+ *
+ * This method is responsible for checking bridge state correctness.
+ * It can also check the state of the surrounding components in chain
+ * to make sure the whole pipeline can work properly.
+ *
+ * &drm_bridge_funcs.atomic_check() hooks are called in reverse
+ * order (from the last to the first bridge).
+ *
+ * This method is optional. &drm_bridge_funcs.mode_fixup() is not
+ * called when &drm_bridge_funcs.atomic_check() is implemented, so only
+ * one of them should be provided.
+ *
+ * RETURNS:
+ * zero if the check passed, a negative error code otherwise.
+ */
+ int (*atomic_check)(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state);
+
/**
* @atomic_reset:
*
@@ -511,6 +535,9 @@ void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
void drm_bridge_chain_pre_enable(struct drm_bridge *bridge);
void drm_bridge_chain_enable(struct drm_bridge *bridge);
+int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state);
void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
struct drm_atomic_state *state);
void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
--
2.21.0
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