Re: [PATCH 1/3] drm/atomic-helper: Export framebuffer_changed()

[Daniel Vetter]

On Thu, Jan 14, 2016 at 02:39:40PM +0000, John Keeping wrote:
> The Rockchip driver cannot use drm_atomic_helper_wait_for_vblanks()
> because it has hardware counters for neither vblanks nor scanlines.
> 
> In order to simplify re-implementing the functionality for this driver,
> export the framebuffer_changed() helper so it can be reused.
> 
> Signed-off-by: John Keeping <john@xxxxxxxxxxxx>

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> And since I don't
expect anyone else to need this anytime soon probably best you just pull
this in through rockchip trees.

Cheers, Daniel

> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 24 ++++++++++++++++++++----
>  include/drm/drm_atomic_helper.h     |  4 ++++
>  2 files changed, 24 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 268d37f..7449293 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -948,9 +948,23 @@ static void wait_for_fences(struct drm_device *dev,
>  	}
>  }
>  
> -static bool framebuffer_changed(struct drm_device *dev,
> -				struct drm_atomic_state *old_state,
> -				struct drm_crtc *crtc)
> +/**
> + * drm_atomic_helper_framebuffer_changed - check if framebuffer has changed
> + * @dev: DRM device
> + * @old_state: atomic state object with old state structures
> + * @crtc: DRM crtc
> + *
> + * Checks whether the framebuffer used for this CRTC changes as a result of
> + * the atomic update.  This is useful for drivers which cannot use
> + * drm_atomic_helper_wait_for_vblanks() and need to reimplement its
> + * functionality.
> + *
> + * Returns:
> + * true if the framebuffer changed.
> + */
> +bool drm_atomic_helper_framebuffer_changed(struct drm_device *dev,
> +					   struct drm_atomic_state *old_state,
> +					   struct drm_crtc *crtc)
>  {
>  	struct drm_plane *plane;
>  	struct drm_plane_state *old_plane_state;
> @@ -967,6 +981,7 @@ static bool framebuffer_changed(struct drm_device *dev,
>  
>  	return false;
>  }
> +EXPORT_SYMBOL(drm_atomic_helper_framebuffer_changed);
>  
>  /**
>   * drm_atomic_helper_wait_for_vblanks - wait for vblank on crtcs
> @@ -1001,7 +1016,8 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
>  		if (old_state->legacy_cursor_update)
>  			continue;
>  
> -		if (!framebuffer_changed(dev, old_state, crtc))
> +		if (!drm_atomic_helper_framebuffer_changed(dev,
> +				old_state, crtc))
>  			continue;
>  
>  		ret = drm_crtc_vblank_get(crtc);
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index a286cce..74fce78 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -42,6 +42,10 @@ int drm_atomic_helper_commit(struct drm_device *dev,
>  			     struct drm_atomic_state *state,
>  			     bool async);
>  
> +bool drm_atomic_helper_framebuffer_changed(struct drm_device *dev,
> +					   struct drm_atomic_state *old_state,
> +					   struct drm_crtc *crtc);
> +
>  void drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
>  					struct drm_atomic_state *old_state);
>  
> -- 
> 2.7.0.226.gfe986fe
> 

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