[Intel-gfx] [PATCH 3/6] drm/i915: Always prepare planes at the start of an atomic commit

[Daniel Vetter]

On Sun, Aug 21, 2016 at 02:15:33PM +0100, Chris Wilson wrote:
> The generic atomic helper likes to skip a prepare_plane_fb() if it
> decides that the plane->fb is unchanged. This is wrong for us for a
> couple of reasons:
> 
>  - if the pipe is reconfigured (i.e. a size change) but the framebuffer
>    is untouched, we still have to flush any rendering prior to the
>    reconfiguration to prevent wait-for-scanline GPU hangs
> 
>  - if the framebuffer is rotated, it remains the same but has a
>    different view and a different address.
> 
> Finally, even if the framebuffer is unchanged the flip/modeset should be
> ordered with respect to rendering to the frontbuffer.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Won't this again break the hacks we have to make the cursor happy?

And maybe we should have this in the core helpers even, with a
drm_plane_state->fb_changed.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_atomic_plane.c |  2 --
>  drivers/gpu/drm/i915/intel_display.c      | 60 ++++++++++++++++++++++++-------
>  drivers/gpu/drm/i915/intel_drv.h          |  4 ---
>  3 files changed, 47 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
> index b41bf380f2ab..76a5bbbaaa98 100644
> --- a/drivers/gpu/drm/i915/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
> @@ -190,8 +190,6 @@ static void intel_plane_atomic_update(struct drm_plane *plane,
>  }
>  
>  const struct drm_plane_helper_funcs intel_plane_helper_funcs = {
> -	.prepare_fb = intel_prepare_plane_fb,
> -	.cleanup_fb = intel_cleanup_plane_fb,
>  	.atomic_check = intel_plane_atomic_check,
>  	.atomic_update = intel_plane_atomic_update,
>  };
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index c4096204e5a3..9c769b5c91b8 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -13938,7 +13938,7 @@ static int intel_atomic_check(struct drm_device *dev,
>   *
>   * Returns 0 on success, negative error code on failure.
>   */
> -int
> +static int
>  intel_prepare_plane_fb(struct drm_plane *plane,
>  		       struct drm_plane_state *new_state)
>  {
> @@ -14024,7 +14024,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
>   *
>   * Must be called with struct_mutex held.
>   */
> -void
> +static void
>  intel_cleanup_plane_fb(struct drm_plane *plane,
>  		       struct drm_plane_state *old_state)
>  {
> @@ -14043,6 +14043,49 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
>  		intel_unpin_fb_obj(old_state->fb, old_state->rotation);
>  }
>  
> +static int intel_atomic_commit_prepare_planes(struct drm_atomic_state *state)
> +{
> +	struct drm_plane *plane;
> +	struct drm_plane_state *plane_state;
> +	int i, j, ret;
> +
> +	ret = mutex_lock_interruptible(&state->dev->struct_mutex);
> +	if (ret)
> +		return ret;
> +
> +	for_each_plane_in_state(state, plane, plane_state, i) {
> +		ret = intel_prepare_plane_fb(plane, plane_state);
> +		if (ret)
> +			break;
> +	}
> +
> +	if (ret) {
> +		for_each_plane_in_state(state, plane, plane_state, j) {
> +			if (j >= i)
> +				break;
> +
> +			intel_cleanup_plane_fb(plane, plane_state);
> +		}
> +	}
> +
> +	mutex_unlock(&state->dev->struct_mutex);
> +
> +	return ret;
> +}
> +
> +static void intel_atomic_commit_cleanup_planes(struct drm_atomic_state *state)
> +{
> +	struct drm_plane *plane;
> +	struct drm_plane_state *plane_state;
> +	int i;
> +
> +	mutex_lock(&state->dev->struct_mutex);
> +
> +	for_each_plane_in_state(state, plane, plane_state, i)
> +		intel_cleanup_plane_fb(plane, plane_state);
> +
> +	mutex_unlock(&state->dev->struct_mutex);
> +}
>  
>  static int intel_atomic_prepare_commit(struct drm_device *dev,
>  				       struct drm_atomic_state *state,
> @@ -14065,14 +14108,7 @@ static int intel_atomic_prepare_commit(struct drm_device *dev,
>  			flush_workqueue(dev_priv->wq);
>  	}
>  
> -	ret = mutex_lock_interruptible(&dev->struct_mutex);
> -	if (ret)
> -		return ret;
> -
> -	ret = drm_atomic_helper_prepare_planes(dev, state);
> -	mutex_unlock(&dev->struct_mutex);
> -
> -	return ret;
> +	return intel_atomic_commit_prepare_planes(state);
>  }
>  
>  u32 intel_crtc_get_vblank_counter(struct intel_crtc *crtc)
> @@ -14301,9 +14337,7 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
>  	if (intel_state->modeset)
>  		intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET);
>  
> -	mutex_lock(&dev->struct_mutex);
> -	drm_atomic_helper_cleanup_planes(dev, state);
> -	mutex_unlock(&dev->struct_mutex);
> +	intel_atomic_commit_cleanup_planes(state);
>  
>  	drm_atomic_helper_commit_cleanup_done(state);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index acb42d66fb08..3416796e5343 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1249,10 +1249,6 @@ __intel_framebuffer_create(struct drm_device *dev,
>  void intel_finish_page_flip_cs(struct drm_i915_private *dev_priv, int pipe);
>  void intel_finish_page_flip_mmio(struct drm_i915_private *dev_priv, int pipe);
>  void intel_check_page_flip(struct drm_i915_private *dev_priv, int pipe);
> -int intel_prepare_plane_fb(struct drm_plane *plane,
> -			   struct drm_plane_state *new_state);
> -void intel_cleanup_plane_fb(struct drm_plane *plane,
> -			    struct drm_plane_state *old_state);
>  int intel_plane_atomic_get_property(struct drm_plane *plane,
>  				    const struct drm_plane_state *state,
>  				    struct drm_property *property,
> -- 
> 2.9.3
> 

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