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@collabora.com --- 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,