[PATCH 4/4] drm: Resurrect atomic rmfb code, v2

[Daniel Vetter]

On Thu, Dec 15, 2016 at 03:29:45PM +0100, Maarten Lankhorst wrote:
> From: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> This was somehow lost between v3 and the merged version in Maarten's
> patch merged as:
> 
> commit f2d580b9a8149735cbc4b59c4a8df60173658140
> Author: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Date:   Wed May 4 14:38:26 2016 +0200
> 
>     drm/core: Do not preserve framebuffer on rmfb, v4.
> 
> Actual code copied from Maarten's patch, but with the slight change to
> just use dev->mode_config.funcs->atomic_commit to decide whether to
> use the atomic path or not.
> 
> v2:
> - Remove plane->fb assignment, done by drm_atomic_clean_old_fb.
> - Add WARN_ON when atomic_remove_fb fails.
> - Always call drm_atomic_state_put.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

Would be great if someone else could r-b this, I've proven pretty well
that I don't understand the complexity here :(
-Daniel

> ---
>  drivers/gpu/drm/drm_atomic.c        | 64 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_crtc_internal.h |  1 +
>  drivers/gpu/drm/drm_framebuffer.c   |  7 ++++
>  3 files changed, 72 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index d1d252261bf1..23a3845542e1 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -2059,6 +2059,70 @@ static void complete_crtc_signaling(struct drm_device *dev,
>  	kfree(fence_state);
>  }
>  
> +int drm_atomic_remove_fb(struct drm_framebuffer *fb)
> +{
> +	struct drm_modeset_acquire_ctx ctx;
> +	struct drm_device *dev = fb->dev;
> +	struct drm_atomic_state *state;
> +	struct drm_plane *plane;
> +	int ret = 0;
> +	unsigned plane_mask;
> +
> +	state = drm_atomic_state_alloc(dev);
> +	if (!state)
> +		return -ENOMEM;
> +
> +	drm_modeset_acquire_init(&ctx, 0);
> +	state->acquire_ctx = &ctx;
> +
> +retry:
> +	plane_mask = 0;
> +	ret = drm_modeset_lock_all_ctx(dev, &ctx);
> +	if (ret)
> +		goto unlock;
> +
> +	drm_for_each_plane(plane, dev) {
> +		struct drm_plane_state *plane_state;
> +
> +		if (plane->state->fb != fb)
> +			continue;
> +
> +		plane_state = drm_atomic_get_plane_state(state, plane);
> +		if (IS_ERR(plane_state)) {
> +			ret = PTR_ERR(plane_state);
> +			goto unlock;
> +		}
> +
> +		drm_atomic_set_fb_for_plane(plane_state, NULL);
> +		ret = drm_atomic_set_crtc_for_plane(plane_state, NULL);
> +		if (ret)
> +			goto unlock;
> +
> +		plane_mask |= BIT(drm_plane_index(plane));
> +
> +		plane->old_fb = plane->fb;
> +	}
> +
> +	if (plane_mask)
> +		ret = drm_atomic_commit(state);
> +
> +unlock:
> +	if (plane_mask)
> +		drm_atomic_clean_old_fb(dev, plane_mask, ret);
> +
> +	if (ret == -EDEADLK) {
> +		drm_modeset_backoff(&ctx);
> +		goto retry;
> +	}
> +
> +	drm_atomic_state_put(state);
> +
> +	drm_modeset_drop_locks(&ctx);
> +	drm_modeset_acquire_fini(&ctx);
> +
> +	return ret;
> +}
> +
>  int drm_mode_atomic_ioctl(struct drm_device *dev,
>  			  void *data, struct drm_file *file_priv)
>  {
> diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
> index cdf6860c9d22..121e250853d2 100644
> --- a/drivers/gpu/drm/drm_crtc_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_internal.h
> @@ -178,6 +178,7 @@ int drm_atomic_get_property(struct drm_mode_object *obj,
>  			    struct drm_property *property, uint64_t *val);
>  int drm_mode_atomic_ioctl(struct drm_device *dev,
>  			  void *data, struct drm_file *file_priv);
> +int drm_atomic_remove_fb(struct drm_framebuffer *fb);
>  
>  
>  /* drm_plane.c */
> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
> index cbf0c893f426..c358bf8280a8 100644
> --- a/drivers/gpu/drm/drm_framebuffer.c
> +++ b/drivers/gpu/drm/drm_framebuffer.c
> @@ -770,6 +770,12 @@ void drm_framebuffer_remove(struct drm_framebuffer *fb)
>  	 * in this manner.
>  	 */
>  	if (drm_framebuffer_read_refcount(fb) > 1) {
> +		if (dev->mode_config.funcs->atomic_commit) {
> +			int ret = drm_atomic_remove_fb(fb);
> +			WARN(ret, "atomic remove_fb failed with %i\n", ret);
> +			goto out;
> +		}
> +
>  		drm_modeset_lock_all(dev);
>  		/* remove from any CRTC */
>  		drm_for_each_crtc(crtc, dev) {
> @@ -787,6 +793,7 @@ void drm_framebuffer_remove(struct drm_framebuffer *fb)
>  		drm_modeset_unlock_all(dev);
>  	}
>  
> +out:
>  	drm_framebuffer_unreference(fb);
>  }
>  EXPORT_SYMBOL(drm_framebuffer_remove);
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch