[PATCH 04/14] drm: add helper to implement legacy dirtyfb

[Daniel Vetter]

On Wed, Sep 05, 2018 at 04:38:51PM -0700, Deepak Rawat wrote:
> From: Rob Clark <robdclark at gmail.com>
> 
> Add an atomic helper to implement dirtyfb support.  This is needed to
> support DSI command-mode panels with x11 userspace (ie. when we can't
> rely on pageflips to trigger a flush to the panel).
> 
> v2: Modified the helper to use plane fb_damage_clips property and
> removed plane_state::dirty flag.
> 
> Signed-off-by: Rob Clark <robdclark at gmail.com>
> Signed-off-by: Deepak Rawat <drawat at vmware.com>
> ---
>  drivers/gpu/drm/drm_damage_helper.c | 116 ++++++++++++++++++++++++++++
>  include/drm/drm_damage_helper.h     |   4 +
>  2 files changed, 120 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
> index 7d70f6001889..b016ec375295 100644
> --- a/drivers/gpu/drm/drm_damage_helper.c
> +++ b/drivers/gpu/drm/drm_damage_helper.c
> @@ -26,6 +26,7 @@
>   *
>   * Authors:
>   * Deepak Rawat <drawat at vmware.com>
> + * Rob Clark <robdclark at gmail.com>
>   *
>   **************************************************************************/
>  
> @@ -81,6 +82,21 @@ static int convert_fixed_to_32(int fixed)
>  	return ((fixed >> 15) & 1) + (fixed >> 16);
>  }
>  
> +static void convert_clip_rect_to_rect(const struct drm_clip_rect *src,
> +				      struct drm_rect *dest,
> +				      uint32_t num_clips)

I think we need to use drm_mode_rect here, because it's essentially the
uapi one.

> +{
> +	while (num_clips > 0) {
> +		dest->x1 = src->x1;
> +		dest->y1 = src->y1;
> +		dest->x2 = src->x2;
> +		dest->y2 = src->y2;
> +		src++;
> +		dest++;
> +		num_clips--;
> +	}
> +}
> +
>  /**
>   * drm_plane_enable_fb_damage_clips - enables plane fb damage clips property
>   * @plane: plane on which to enable damage clips property
> @@ -183,3 +199,103 @@ drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter,
>  	return ret;
>  }
>  EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next);
> +
> +/**
> + * drm_atomic_helper_dirtyfb - helper for dirtyfb
> + * @fb: DRM framebuffer
> + * @file_priv: drm file for the ioctl call
> + * @flags: dirty fb annotate flags
> + * @color: color for annotate fill
> + * @clips: dirty region
> + * @num_clips: count of clip in clips
> + *
> + * A helper to implement drm_framebuffer_funcs::dirty. This helper will do a
> + * full update in case of annotate flags.
> + *
> + * Returns: Zero on success, negative errno on failure.
> + */
> +int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb,
> +			      struct drm_file *file_priv, unsigned flags,
> +			      unsigned color, struct drm_clip_rect *clips,
> +			      unsigned num_clips)
> +{
> +	struct drm_modeset_acquire_ctx ctx;
> +	struct drm_property_blob *damage = NULL;
> +	struct drm_atomic_state *state;
> +	struct drm_plane *plane;
> +	struct drm_rect *rects = NULL;
> +	int ret = 0;
> +
> +	/*
> +	 * When called from ioctl, we are interruptable, but not when called
> +	 * internally (ie. defio worker)
> +	 */
> +	drm_modeset_acquire_init(&ctx,
> +		file_priv ? DRM_MODESET_ACQUIRE_INTERRUPTIBLE : 0);
> +
> +	state = drm_atomic_state_alloc(fb->dev);
> +	if (!state) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +	state->acquire_ctx = &ctx;
> +
> +	WARN_ONCE(flags & DRM_MODE_FB_DIRTY_FLAGS,
> +		  "Full update for dirtyfb with DRM_MODE_FB_DIRTY_FLAGS\n");

User-triggerable backtrace isn't good. I think you just need to handle the
FILL/COPY meaning.

For COPY we need to ignore all the odd rects (iirc those are the sources).
FILL we can just handle. See e.g. what tinydrm_merge_clips does.

Otherwise I think this looks good.
-Daniel

> +
> +	if (!(flags & DRM_MODE_FB_DIRTY_FLAGS)) {
> +		rects = kcalloc(num_clips, sizeof(*rects), GFP_KERNEL);
> +		if (!rects) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +
> +		convert_clip_rect_to_rect(clips, rects, num_clips);
> +		damage = drm_property_create_blob(fb->dev,
> +						  num_clips * sizeof(*rects),
> +						  rects);
> +		if (IS_ERR(damage)) {
> +			ret = PTR_ERR(damage);
> +			damage = NULL;
> +			goto out;
> +		}
> +	}
> +
> +retry:
> +	drm_for_each_plane(plane, fb->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 out;
> +		}
> +
> +		drm_property_replace_blob(&plane_state->fb_damage_clips,
> +					  damage);
> +	}
> +
> +	ret = drm_atomic_commit(state);
> +
> +out:
> +	if (ret == -EDEADLK) {
> +		drm_atomic_state_clear(state);
> +		ret = drm_modeset_backoff(&ctx);
> +		if (!ret)
> +			goto retry;
> +	}
> +
> +	drm_property_blob_put(damage);
> +	kfree(rects);
> +	drm_atomic_state_put(state);
> +
> +	drm_modeset_drop_locks(&ctx);
> +	drm_modeset_acquire_fini(&ctx);
> +
> +	return ret;
> +
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
> diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
> index 1f988f7fdd72..9d5c9444761b 100644
> --- a/include/drm/drm_damage_helper.h
> +++ b/include/drm/drm_damage_helper.h
> @@ -89,5 +89,9 @@ drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
>  bool
>  drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter,
>  				   struct drm_rect *rect);
> +int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb,
> +			      struct drm_file *file_priv, unsigned flags,
> +			      unsigned color, struct drm_clip_rect *clips,
> +			      unsigned num_clips);
>  
>  #endif
> -- 
> 2.17.1
> 

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