Re: [PATCH 3/4] drm/vc4: Use the atomic state's commit workqueue.

Boris Brezillon
2017-06-22T08:06:18Z

On Wed, 21 Jun 2017 11:50:01 -0700
Eric Anholt <eric@anholt.net> wrote:

> Now that we're using the atomic helpers for fence waits, we can use
> the same codepath as drm_atomic_helper_commit() does for async,
> getting rid of our custom vc4_commit struct.
>
> Signed-off-by: Eric Anholt <eric@anholt.net>

Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

And with this rework, you also fix the leak I introduced in commit
34c8ea400ff6 ("drm/vc4: Mimic drm_atomic_helper_commit() behavior").

> ---
> drivers/gpu/drm/vc4/vc4_kms.c | 71 ++++++++-----------------------------------
> 1 file changed, 13 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
> index 6b1ccea76243..b371879c3901 100644
> --- a/drivers/gpu/drm/vc4/vc4_kms.c
> +++ b/drivers/gpu/drm/vc4/vc4_kms.c
> @@ -29,16 +29,9 @@ static void vc4_output_poll_changed(struct drm_device *dev)
> drm_fbdev_cma_hotplug_event(vc4->fbdev);
> }
>
> -struct vc4_commit {
> - struct drm_device *dev;
> - struct drm_atomic_state *state;
> - struct vc4_seqno_cb cb;
> -};
> -
> static void
> -vc4_atomic_complete_commit(struct vc4_commit *c)
> +vc4_atomic_complete_commit(struct drm_atomic_state *state)
> {
> - struct drm_atomic_state *state = c->state;
> struct drm_device *dev = state->dev;
> struct vc4_dev *vc4 = to_vc4_dev(dev);
>
> @@ -72,28 +65,14 @@ vc4_atomic_complete_commit(struct vc4_commit *c)
> drm_atomic_state_put(state);
>
> up(&vc4->async_modeset);
> -
> - kfree(c);
> -}
> -
> -static void
> -vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb)
> -{
> - struct vc4_commit *c = container_of(cb, struct vc4_commit, cb);
> -
> - vc4_atomic_complete_commit(c);
> }
>
> -static struct vc4_commit *commit_init(struct drm_atomic_state *state)
> +static void commit_work(struct work_struct *work)
> {
> - struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
> -
> - if (!c)
> - return NULL;
> - c->dev = state->dev;
> - c->state = state;
> -
> - return c;
> + struct drm_atomic_state *state = container_of(work,
> + struct drm_atomic_state,
> + commit_work);
> + vc4_atomic_complete_commit(state);
> }
>
> /**
> @@ -115,29 +94,19 @@ static int vc4_atomic_commit(struct drm_device *dev,
> {
> struct vc4_dev *vc4 = to_vc4_dev(dev);
> int ret;
> - int i;
> - uint64_t wait_seqno = 0;
> - struct vc4_commit *c;
> - struct drm_plane *plane;
> - struct drm_plane_state *new_state;
> -
> - c = commit_init(state);
> - if (!c)
> - return -ENOMEM;
>
> ret = drm_atomic_helper_setup_commit(state, nonblock);
> if (ret)
> return ret;
>
> + INIT_WORK(&state->commit_work, commit_work);
> +
> ret = down_interruptible(&vc4->async_modeset);
> - if (ret) {
> - kfree(c);
> + if (ret)
> return ret;
> - }
>
> ret = drm_atomic_helper_prepare_planes(dev, state);
> if (ret) {
> - kfree(c);
> up(&vc4->async_modeset);
> return ret;
> }
> @@ -146,22 +115,11 @@ static int vc4_atomic_commit(struct drm_device *dev,
> ret = drm_atomic_helper_wait_for_fences(dev, state, true);
> if (ret) {
> drm_atomic_helper_cleanup_planes(dev, state);
> - kfree(c);
> up(&vc4->async_modeset);
> return ret;
> }
> }
>
> - for_each_plane_in_state(state, plane, new_state, i) {
> - if ((plane->state->fb != new_state->fb) && new_state->fb) {
> - struct drm_gem_cma_object *cma_bo =
> - drm_fb_cma_get_gem_obj(new_state->fb, 0);
> - struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
> -
> - wait_seqno = max(bo->seqno, wait_seqno);
> - }
> - }
> -
> /*
> * This is the point of no return - everything below never fails except
> * when the hw goes bonghits. Which means we can commit the new state on
> @@ -187,13 +145,10 @@ static int vc4_atomic_commit(struct drm_device *dev,
> */
>
> drm_atomic_state_get(state);
> - if (nonblock) {
> - vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
> - vc4_atomic_complete_commit_seqno_cb);
> - } else {
> - vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false);
> - vc4_atomic_complete_commit(c);
> - }
> + if (nonblock)
> + queue_work(system_unbound_wq, &state->commit_work);
> + else
> + vc4_atomic_complete_commit(state);
>
> return 0;
> }