On Tue, Aug 11, 2015 at 01:37:43PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> This function can be used to duplicate an atomic state object. This is
> useful for example to implement suspend/resume, where the state before
> suspend can be saved and restored upon resume.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 90 +++++++++++++++++++++++++++++++++++++
> include/drm/drm_atomic_helper.h | 2 +
> 2 files changed, 92 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index fd06595c2ee5..f842499ca79e 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -2358,6 +2358,96 @@ drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector)
> EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
>
> /**
> + * drm_atomic_helper_duplicate_state - duplicate an atomic state object
> + * @dev: DRM device
> + *
> + * Makes a copy of the current atomic state by looping over all objects and
> + * duplicating their respective states.
This needs a big warning that drivers better know what they're doing for
two reasons: It promises that atomic states can be treated as persistent
bits (e.g. if a driver has an update-counter somewhere that won't work).
And it drops locks again so will race if that's not otherwise excluded
(like in suspend/resume where nothing else is allowed to run if you shut
down fbcon with fbdev_set_suspend() before calling this function).
Maybe needs some rewording, but all of the above (including details like
fbdev_set_suspend) must be mentioned.
> + *
> + * Returns: A pointer to the copy of the atomic state object on success or an
> + * ERR_PTR()-encoded error code on failure.
> + */
> +struct drm_atomic_state *
> +drm_atomic_helper_duplicate_state(struct drm_device *dev)
> +{
> + struct drm_modeset_acquire_ctx ctx;
> + struct drm_atomic_state *state;
> + struct drm_connector *conn;
> + struct drm_plane *plane;
> + struct drm_crtc *crtc;
> + int err;
> +
> + state = drm_atomic_state_alloc(dev);
> + if (!state)
> + return ERR_PTR(-ENOMEM);
> +
> + drm_modeset_acquire_init(&ctx, 0);
> + state->acquire_ctx = &ctx;
> +
> + err = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
> + if (err < 0)
> + goto free;
Just use drm_modeset_lock_all. You need them all anyway and for
suspend/resume there won't be any contention anyway.
Otherwise lgtm.
-Daniel
> +
> + drm_for_each_crtc(crtc, dev) {
> + unsigned int index = drm_crtc_index(crtc);
> + struct drm_crtc_state *crtc_state;
> +
> + crtc_state = crtc->funcs->atomic_duplicate_state(crtc);
> + if (!crtc_state) {
> + err = -ENOMEM;
> + goto unlock;
> + }
> +
> + state->crtc_states[index] = crtc_state;
> + state->crtcs[index] = crtc;
> + crtc_state->state = state;
> + }
> +
> + drm_for_each_plane(plane, dev) {
> + unsigned int index = drm_plane_index(plane);
> + struct drm_plane_state *plane_state;
> +
> + plane_state = plane->funcs->atomic_duplicate_state(plane);
> + if (!plane_state) {
> + err = -ENOMEM;
> + goto unlock;
> + }
> +
> + state->plane_states[index] = plane_state;
> + state->planes[index] = plane;
> + plane_state->state = state;
> + }
> +
> + drm_for_each_connector(conn, dev) {
> + unsigned int index = drm_connector_index(conn);
> + struct drm_connector_state *conn_state;
> +
> + conn_state = conn->funcs->atomic_duplicate_state(conn);
> + if (!conn_state) {
> + err = -ENOMEM;
> + goto unlock;
> + }
> +
> + state->connector_states[index] = conn_state;
> + state->connectors[index] = conn;
> + conn_state->state = state;
> + }
> +
> +unlock:
> + drm_modeset_drop_locks(&ctx);
> +free:
> + drm_modeset_acquire_fini(&ctx);
> +
> + if (err < 0) {
> + drm_atomic_state_free(state);
> + state = ERR_PTR(err);
> + }
> +
> + return state;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_duplicate_state);
> +
> +/**
> * __drm_atomic_helper_connector_destroy_state - release connector state
> * @connector: connector object
> * @state: connector state object to release
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 4ffe9dca07c4..5d27612997ce 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -118,6 +118,8 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
> struct drm_connector_state *state);
> struct drm_connector_state *
> drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector);
> +struct drm_atomic_state *
> +drm_atomic_helper_duplicate_state(struct drm_device *dev);
> void
> __drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
> struct drm_connector_state *state);
> --
> 2.4.5
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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