Re: [RFC][PATCH 1/5] drm: Introduce scaling filter property

[Daniel Vetter]

On Tue, Mar 10, 2020 at 06:01:06PM +0200, Ville Syrjälä wrote:
> On Tue, Feb 25, 2020 at 12:35:41PM +0530, Pankaj Bharadiya wrote:
> > Introduce new scaling filter property to allow userspace to select
> > the driver's default scaling filter or Nearest-neighbor(NN) filter
> > for upscaling operations on crtc/plane.
> > 
> > Drivers can set up this property for a plane by calling
> > drm_plane_enable_scaling_filter() and for a CRTC by calling
> > drm_crtc_enable_scaling_filter().
> > 
> > NN filter works by filling in the missing color values in the upscaled
> > image with that of the coordinate-mapped nearest source pixel value.
> > 
> > NN filter for integer multiple scaling can be particularly useful for
> > for pixel art games that rely on sharp, blocky images to deliver their
> > distinctive look.
> > 
> > Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@xxxxxxxxx>
> > Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
> > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> > ---
> >  drivers/gpu/drm/drm_atomic_uapi.c |  8 +++++++
> >  drivers/gpu/drm/drm_crtc.c        | 16 ++++++++++++++
> >  drivers/gpu/drm/drm_mode_config.c | 13 ++++++++++++
> >  drivers/gpu/drm/drm_plane.c       | 35 +++++++++++++++++++++++++++++++
> >  include/drm/drm_crtc.h            | 10 +++++++++
> >  include/drm/drm_mode_config.h     |  6 ++++++
> >  include/drm/drm_plane.h           | 14 +++++++++++++
> >  7 files changed, 102 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> > index a1e5e262bae2..4e3c1f3176e4 100644
> > --- a/drivers/gpu/drm/drm_atomic_uapi.c
> > +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> > @@ -435,6 +435,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> >  		return ret;
> >  	} else if (property == config->prop_vrr_enabled) {
> >  		state->vrr_enabled = val;
> > +	} else if (property == config->scaling_filter_property) {
> > +		state->scaling_filter = val;
> 
> I think we want a per-plane/per-crtc prop for this. If we start adding
> more filters we are surely going to need different sets for different hw
> blocks.

In the past we've only done that once we have a demonstrated need. Usually
the patch to move the property to a per-object location isn't a lot of
churn.
-Daniel

> 
> >  	} else if (property == config->degamma_lut_property) {
> >  		ret = drm_atomic_replace_property_blob_from_id(dev,
> >  					&state->degamma_lut,
> > @@ -503,6 +505,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
> >  		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
> >  	else if (property == config->prop_out_fence_ptr)
> >  		*val = 0;
> > +	else if (property == config->scaling_filter_property)
> > +		*val = state->scaling_filter;
> >  	else if (crtc->funcs->atomic_get_property)
> >  		return crtc->funcs->atomic_get_property(crtc, state, property, val);
> >  	else
> > @@ -583,6 +587,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
> >  					sizeof(struct drm_rect),
> >  					&replaced);
> >  		return ret;
> > +	} else if (property == config->scaling_filter_property) {
> > +		state->scaling_filter = val;
> >  	} else if (plane->funcs->atomic_set_property) {
> >  		return plane->funcs->atomic_set_property(plane, state,
> >  				property, val);
> > @@ -641,6 +647,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
> >  	} else if (property == config->prop_fb_damage_clips) {
> >  		*val = (state->fb_damage_clips) ?
> >  			state->fb_damage_clips->base.id : 0;
> > +	} else if (property == config->scaling_filter_property) {
> > +		*val = state->scaling_filter;
> >  	} else if (plane->funcs->atomic_get_property) {
> >  		return plane->funcs->atomic_get_property(plane, state, property, val);
> >  	} else {
> > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> > index 4936e1080e41..1ce7b2ac9eb5 100644
> > --- a/drivers/gpu/drm/drm_crtc.c
> > +++ b/drivers/gpu/drm/drm_crtc.c
> > @@ -748,3 +748,19 @@ int drm_mode_crtc_set_obj_prop(struct drm_mode_object *obj,
> >  
> >  	return ret;
> >  }
> > +
> > +/**
> > + * drm_crtc_enable_scaling_filter - Enables crtc scaling filter property.
> > + * @crtc: CRTC on which to enable scaling filter property.
> > + *
> > + * This function lets driver to enable the scaling filter property on a crtc.
> > + */
> > +void drm_crtc_enable_scaling_filter(struct drm_crtc *crtc)
> > +{
> > +	struct drm_device *dev = crtc->dev;
> > +
> > +	drm_object_attach_property(&crtc->base,
> > +				   dev->mode_config.scaling_filter_property,
> > +				   0);
> > +}
> > +EXPORT_SYMBOL(drm_crtc_enable_scaling_filter);
> > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> > index 08e6eff6a179..1024a8d1cd5d 100644
> > --- a/drivers/gpu/drm/drm_mode_config.c
> > +++ b/drivers/gpu/drm/drm_mode_config.c
> > @@ -214,6 +214,11 @@ static const struct drm_prop_enum_list drm_plane_type_enum_list[] = {
> >  	{ DRM_PLANE_TYPE_CURSOR, "Cursor" },
> >  };
> >  
> > +static const struct drm_prop_enum_list drm_scaling_filter_enum_list[] = {
> > +	{ DRM_SCALING_FILTER_DEFAULT, "Default" },
> > +	{ DRM_SCALING_FILTER_NEAREST_NEIGHBOR, "Nearest Neighbor" },
> > +};
> > +
> >  static int drm_mode_create_standard_properties(struct drm_device *dev)
> >  {
> >  	struct drm_property *prop;
> > @@ -370,6 +375,14 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >  		return -ENOMEM;
> >  	dev->mode_config.modifiers_property = prop;
> >  
> > +	prop = drm_property_create_enum(dev, 0,
> > +				"SCALING_FILTER",
> > +				drm_scaling_filter_enum_list,
> > +				ARRAY_SIZE(drm_scaling_filter_enum_list));
> > +	if (!prop)
> > +		return -ENOMEM;
> > +	dev->mode_config.scaling_filter_property = prop;
> > +
> >  	return 0;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> > index d6ad60ab0d38..ace7ee2775c8 100644
> > --- a/drivers/gpu/drm/drm_plane.c
> > +++ b/drivers/gpu/drm/drm_plane.c
> > @@ -1221,3 +1221,38 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
> >  
> >  	return ret;
> >  }
> > +
> > +/**
> > + * DOC: Scaling filter property
> > + *
> > + *
> > + * SCALING_FILTER:
> > + *
> > + *	Indicates scaling filter to be used for CRTC/plane scaler
> > + *
> > + *	The value of this property can be one of the following:
> > + *	Default:
> > + *		Driver's default scaling filter
> > + *	Nearest Neighbor:
> > + *		Nearest Neighbor scaling filter
> > + *
> > + * Drivers can set up this property for a plane by calling
> > + * drm_plane_enable_scaling_filter() and for a CRTC by calling
> > + * drm_crtc_enable_scaling_filter()
> > + */
> > +
> > +/**
> > + * drm_plane_enable_scaling_filter - Enables plane scaling filter property.
> > + * @plane: Plane on which to enable scaling filter property.
> > + *
> > + * This function lets driver to enable the scaling filter property on a plane.
> > + */
> > +void drm_plane_enable_scaling_filter(struct drm_plane *plane)
> > +{
> > +	struct drm_device *dev = plane->dev;
> > +
> > +	drm_object_attach_property(&plane->base,
> > +				   dev->mode_config.scaling_filter_property,
> > +				   0);
> > +}
> > +EXPORT_SYMBOL(drm_plane_enable_scaling_filter);
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 59b51a09cae6..770f9328a5ba 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -58,6 +58,7 @@ struct device_node;
> >  struct dma_fence;
> >  struct edid;
> >  
> > +
> >  static inline int64_t U642I64(uint64_t val)
> >  {
> >  	return (int64_t)*((int64_t *)&val);
> > @@ -296,6 +297,13 @@ struct drm_crtc_state {
> >  	 */
> >  	u32 target_vblank;
> >  
> > +	/**
> > +	 * @scaling_filter:
> > +	 *
> > +	 * Scaling filter mode to be applied
> > +	 */
> > +	enum drm_scaling_filter scaling_filter;
> > +
> >  	/**
> >  	 * @async_flip:
> >  	 *
> > @@ -1266,4 +1274,6 @@ static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev,
> >  #define drm_for_each_crtc(crtc, dev) \
> >  	list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head)
> >  
> > +void drm_crtc_enable_scaling_filter(struct drm_crtc *crtc);
> > +
> >  #endif /* __DRM_CRTC_H__ */
> > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > index 3bcbe30339f0..8c308ae1056d 100644
> > --- a/include/drm/drm_mode_config.h
> > +++ b/include/drm/drm_mode_config.h
> > @@ -914,6 +914,12 @@ struct drm_mode_config {
> >  	 */
> >  	struct drm_property *modifiers_property;
> >  
> > +	/**
> > +	 * @scaling_filter_property: CRTC/plane property to apply a particular
> > +	 * filter while scaling.
> > +	 */
> > +	struct drm_property *scaling_filter_property;
> > +
> >  	/* cursor size */
> >  	uint32_t cursor_width, cursor_height;
> >  
> > diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
> > index 3f396d94afe4..2bc665cc6071 100644
> > --- a/include/drm/drm_plane.h
> > +++ b/include/drm/drm_plane.h
> > @@ -35,6 +35,11 @@ struct drm_crtc;
> >  struct drm_printer;
> >  struct drm_modeset_acquire_ctx;
> >  
> > +
> > +enum drm_scaling_filter {
> > +	DRM_SCALING_FILTER_DEFAULT,
> > +	DRM_SCALING_FILTER_NEAREST_NEIGHBOR,
> > +};
> >  /**
> >   * struct drm_plane_state - mutable plane state
> >   *
> > @@ -214,6 +219,13 @@ struct drm_plane_state {
> >  	 */
> >  	bool visible;
> >  
> > +	/**
> > +	 * @scaling_filter:
> > +	 *
> > +	 * Scaling filter mode to be applied
> > +	 */
> > +	enum drm_scaling_filter scaling_filter;
> > +
> >  	/**
> >  	 * @commit: Tracks the pending commit to prevent use-after-free conditions,
> >  	 * and for async plane updates.
> > @@ -862,4 +874,6 @@ drm_plane_get_damage_clips(const struct drm_plane_state *state)
> >  					state->fb_damage_clips->data : NULL);
> >  }
> >  
> > +void drm_plane_enable_scaling_filter(struct drm_plane *plane);
> > +
> >  #endif
> > -- 
> > 2.23.0
> 
> -- 
> Ville Syrjälä
> Intel

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