The .force() connector callback is invoked by drm_helper_probe_single_connector_modes() while the modeset acquire context it created is live, but the hook signature provides no way to pass it down, e.g. to support implementations needing to lock further objects.
Add a .force_ctx() variant to drm_connector_helper_funcs, taking the acquire context and returning an error code, so that -EDEADLK propagates into the existing retry path. When provided, it takes precedence over drm_connector_funcs' .force(), which is kept for existing users. This is a prerequisite for SCDC status synchronization in the HDMI connector framework. Signed-off-by: Cristian Ciocaltea <[email protected]> --- drivers/gpu/drm/drm_probe_helper.c | 14 +++++++++++++- include/drm/drm_connector.h | 6 ++++++ include/drm/drm_modeset_helper_vtables.h | 28 ++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index e26ead5b5e58..918255bcfa09 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -559,6 +559,7 @@ static int __drm_helper_update_and_validate(struct drm_connector *connector, int drm_helper_probe_single_connector_modes(struct drm_connector *connector, uint32_t maxX, uint32_t maxY) { + const struct drm_connector_helper_funcs *funcs = connector->helper_private; struct drm_device *dev = connector->dev; struct drm_display_mode *mode; int count = 0, ret; @@ -592,8 +593,19 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector, connector->status = connector_status_connected; else connector->status = connector_status_disconnected; - if (connector->funcs->force) + + if (funcs && funcs->force_ctx) { + ret = funcs->force_ctx(connector, &ctx); + if (ret == -EDEADLK) { + drm_modeset_backoff(&ctx); + goto retry; + } else if (ret < 0) { + drm_dbg_kms(dev, "[CONNECTOR:%d:%s] force_ctx failed: %d\n", + connector->base.id, connector->name, ret); + } + } else if (connector->funcs->force) { connector->funcs->force(connector); + } } else { ret = drm_helper_probe_detect(connector, &ctx, true); diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 2a49c4d55f77..a6de3e63b462 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -1603,6 +1603,12 @@ struct drm_connector_funcs { * the sysfs interfaces or on the kernel cmdline. In that case the * @detect callback isn't called. * + * New drivers should implement + * &drm_connector_helper_funcs.force_ctx instead, which gets passed + * the modeset acquire context and thus allows taking additional + * locks. It takes precedence over this callback when both are + * implemented. + * * FIXME: * * Note that this hook is only called by the probe helper. It's not in diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index ca6268945c28..cf5fe5ba2b18 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -921,6 +921,34 @@ struct drm_connector_helper_funcs { struct drm_modeset_acquire_ctx *ctx, bool force); + /** + * @force_ctx: + * + * This function is called to update internal encoder state when the + * connector is forced to a certain state by userspace, either through + * the sysfs interfaces or on the kernel cmdline. In that case the + * @detect_ctx callback isn't called. + * + * This is the atomic version of &drm_connector_funcs.force. When + * both are implemented, this one takes precedence and + * &drm_connector_funcs.force is not called. + * + * To avoid races against concurrent connector state updates, the + * helper libraries always call this with ctx set to a valid context, + * and &drm_mode_config.connection_mutex will always be locked with + * the ctx parameter set to this ctx. This allows taking additional + * locks as required. + * + * RETURNS: + * + * Zero on success, or a negative error code otherwise. This includes + * -EDEADLK when a lock acquisition needs to be restarted, in which + * case the helpers take care of backing off and calling this function + * again. + */ + int (*force_ctx)(struct drm_connector *connector, + struct drm_modeset_acquire_ctx *ctx); + /** * @mode_valid: * -- 2.55.0
