[PATCH 1/3] drm: Introduce scaling filter mode property

[Ville Syrjälä]

On Tue, Oct 22, 2019 at 08:51:20PM +0530, Sharma, Shashank wrote:
> 
> On 10/22/2019 5:56 PM, Ville Syrjälä wrote:
> > On Tue, Oct 22, 2019 at 03:29:44PM +0530, Shashank Sharma wrote:
> >> This patch adds a scaling filter mode porperty
> >> to allow:
> >> - A driver/HW to showcase it's scaling filter capabilities.
> >> - A userspace to pick a desired effect while scaling.
> >>
> >> This option will be particularly useful in the scenarios where
> >> Integer mode scaling is possible, and a UI client wants to pick
> >> filters like Nearest-neighbor applied for non-blurry outputs.
> >>
> >> There was a RFC patch series published, to discus the request to enable
> >> Integer mode scaling by some of the gaming communities, which can be
> >> found here:
> >> https://patchwork.freedesktop.org/series/66175/
> >>
> >> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> >> ---
> >>   drivers/gpu/drm/drm_atomic_uapi.c |  4 ++++
> >>   include/drm/drm_crtc.h            | 26 ++++++++++++++++++++++++++
> >>   include/drm/drm_mode_config.h     |  6 ++++++
> >>   3 files changed, 36 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> >> index 0d466d3b0809..883329453a86 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;
> >>   	} 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
> >> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> >> index 5e9b15a0e8c5..94c5509474a8 100644
> >> --- a/include/drm/drm_crtc.h
> >> +++ b/include/drm/drm_crtc.h
> >> @@ -58,6 +58,25 @@ struct device_node;
> >>   struct dma_fence;
> >>   struct edid;
> >>   
> >> +enum drm_scaling_filters {
> >> +	DRM_SCALING_FILTER_DEFAULT,
> >> +	DRM_SCALING_FILTER_MEDIUM,
> >> +	DRM_SCALING_FILTER_BILINEAR,
> >> +	DRM_SCALING_FILTER_NN,
> >> +	DRM_SCALING_FILTER_NN_IS_ONLY,
> >> +	DRM_SCALING_FILTER_EDGE_ENHANCE,
> >> +	DRM_SCALING_FILTER_INVALID,
> >> +};
> >> +
> >> +static const struct drm_prop_enum_list drm_scaling_filter_enum_list[] = {
> >> +	{ DRM_SCALING_FILTER_DEFAULT, "Default" },
> >> +	{ DRM_SCALING_FILTER_MEDIUM, "Medium" },
> >> +	{ DRM_SCALING_FILTER_BILINEAR, "Bilinear" },
> >> +	{ DRM_SCALING_FILTER_NN, "Nearest Neighbor" },
> >> +	{ DRM_SCALING_FILTER_NN_IS_ONLY, "Integer Mode Scaling" },
> >> +	{ DRM_SCALING_FILTER_INVALID, "Invalid" },
> >> +};
> >> +
> >>   static inline int64_t U642I64(uint64_t val)
> >>   {
> >>   	return (int64_t)*((int64_t *)&val);
> >> @@ -283,6 +302,13 @@ struct drm_crtc_state {
> >>   	 */
> >>   	u32 target_vblank;
> >>   
> >> +	/**
> >> +	 * @scaling_filter:
> >> +	 *
> >> +	 * Scaling filter mode to be applied
> >> +	 */
> >> +	u32 scaling_filter;
> >> +
> >>   	/**
> >>   	 * @async_flip:
> >>   	 *
> >> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> >> index 3bcbe30339f0..efd6fd55770f 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 property to apply a particular filter
> >> +	 * while scaling in panel fitter mode.
> >> +	 */
> >> +	struct drm_property *scaling_filter_property;
> > This needs to per-crtc/plane.
> 
> I am not getting this, why ? It's not different than any other CRTC 
> property like gamma/CSC etc, where we just attach them to corresponding 
> CRTC, isn't it ?

Different crtcs/planes can have different capabilities, and so not all
of them may want to expose all the possible filters.

-- 
Ville Syrjälä
Intel