[RFC weston 2/3] drm-backend: drm-backend changes for setting scaling_fitler

[Sameer Lattannavar]

Modify  existing drm-backend to set_scaling_filter property that
client has requested compositor to do.
drm-backend calls drmset property api of libdrm to do so.

Signed-off-by: Sameer Lattannavar <sameer.lattannavar at intel.com>
---
 libweston/backend-drm/drm-internal.h | 18 ++++++++++++
 libweston/backend-drm/drm.c          | 41 ++++++++++++++++++++++++++--
 libweston/backend-drm/kms.c          | 14 ++++++++++
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/libweston/backend-drm/drm-internal.h b/libweston/backend-drm/drm-internal.h
index 2384a9ac..6cda84f1 100644
--- a/libweston/backend-drm/drm-internal.h
+++ b/libweston/backend-drm/drm-internal.h
@@ -224,12 +224,24 @@ enum wdrm_dpms_state {
 	WDRM_DPMS_STATE__COUNT
 };
 
+enum wdrm_scaling_filters {
+	WDRM_SCALING_FILTER_DEFAULT,
+	WDRM_SCALING_FILTER_MEDIUM,
+	WDRM_SCALING_FILTER_BILINEAR,
+	WDRM_SCALING_FILTER_NN,
+	WDRM_SCALING_FILTER_NN_IS_ONLY,
+	WDRM_SCALING_FILTER_EDGE_ENHANCE,
+	WDRM_SCALING_FILTER_INVALID,
+	WDRM_SCALING_FILTER__COUNT
+};
+
 /**
  * List of properties attached to DRM CRTCs
  */
 enum wdrm_crtc_property {
 	WDRM_CRTC_MODE_ID = 0,
 	WDRM_CRTC_ACTIVE,
+	WDRM_SCALING_FILTER,
 	WDRM_CRTC__COUNT
 };
 
@@ -484,6 +496,12 @@ struct drm_output {
 	/* Holds the properties for the CRTC */
 	struct drm_property_info props_crtc[WDRM_CRTC__COUNT];
 
+	/*To flag if HW supports the Scaling filter as one of the CRTC
+	 *properties for scailing the output
+	 */
+	bool flag_scaling_filter;
+	int scaling_filter_type;
+
 	bool page_flip_pending;
 	bool atomic_complete_pending;
 	bool destroy_pending;
diff --git a/libweston/backend-drm/drm.c b/libweston/backend-drm/drm.c
index e0b1cbd7..6e6ddd72 100644
--- a/libweston/backend-drm/drm.c
+++ b/libweston/backend-drm/drm.c
@@ -768,7 +768,7 @@ drm_plane_create(struct drm_backend *b, const drmModePlane *kplane,
 					       WDRM_PLANE_TYPE__COUNT);
 
 		zpos_range_values =
-			drm_property_get_range_values(&plane->props[WDRM_PLANE_ZPOS], 
+			drm_property_get_range_values(&plane->props[WDRM_PLANE_ZPOS],
 						      props);
 
 		if (zpos_range_values) {
@@ -1120,6 +1120,34 @@ drm_set_dpms(struct weston_output *output_base, enum dpms_enum level)
 		weston_log("drm_set_dpms: couldn't disable output?\n");
 }
 
+/*
+ * If we are upscaling, and the scaling ratios are integer, we can
+ * pick nearest-neighbour method in HW for scaling, which produces
+ * blurless outputs in such scenarios.
+ */
+static void
+drm_set_scaling_filter(struct weston_output *output_base,
+			enum wdrm_scaling_filters filter)
+{
+	weston_log("drm_set_integer_scaling: to set the scaling_filter\n");
+	struct drm_output *output = to_drm_output(output_base);
+	struct drm_backend *b = to_drm_backend(output_base->compositor);
+	int ret;
+
+	if (output->flag_scaling_filter) {
+		ret = drmModeObjectSetProperty(b->drm.fd,  output->crtc_id,
+				DRM_MODE_OBJECT_CRTC,
+				output->props_crtc->prop_id,
+			output->scaling_filter_type);
+		if (ret) {
+			weston_log("drmModeObjectSetProperty: FAILED!!!\n");
+			output->scaling_filter_type =
+				WDRM_SCALING_FILTER_DEFAULT;
+		}
+		weston_log("drmModeObjectSetProperty: Succeeded\n");
+	}
+}
+
 static const char * const connector_type_names[] = {
 	[DRM_MODE_CONNECTOR_Unknown]     = "Unknown",
 	[DRM_MODE_CONNECTOR_VGA]         = "VGA",
@@ -1592,7 +1620,7 @@ drm_output_init_crtc(struct drm_output *output, drmModeRes *resources)
 {
 	struct drm_backend *b = to_drm_backend(output->base.compositor);
 	drmModeObjectPropertiesPtr props;
-	int i;
+	int i, x;
 
 	assert(output->crtc_id == 0);
 
@@ -1614,6 +1642,14 @@ drm_output_init_crtc(struct drm_output *output, drmModeRes *resources)
 	}
 	drm_property_info_populate(b, crtc_props, output->props_crtc,
 				   WDRM_CRTC__COUNT, props);
+	if (output->props_crtc) {
+		for (x = 0; x < WDRM_CRTC__COUNT; x++) {
+			if (strcmp(output->props_crtc->name, "SCALING_FILTERS"))
+				continue;
+			output->flag_scaling_filter = true;
+			output->scaling_filter_type = WDRM_SCALING_FILTER_NN;
+		}
+	}
 	drmModeFreeObjectProperties(props);
 
 	output->scanout_plane =
@@ -1732,6 +1768,7 @@ drm_output_enable(struct weston_output *base)
 	output->base.set_dpms = drm_set_dpms;
 	output->base.switch_mode = drm_output_switch_mode;
 	output->base.set_gamma = drm_output_set_gamma;
+	output->base.set_scaling_filter = drm_set_scaling_filter;
 
 	if (output->cursor_plane)
 		weston_compositor_stack_plane(b->compositor,
diff --git a/libweston/backend-drm/kms.c b/libweston/backend-drm/kms.c
index 192435c7..138b7bf0 100644
--- a/libweston/backend-drm/kms.c
+++ b/libweston/backend-drm/kms.c
@@ -137,9 +137,23 @@ const struct drm_property_info connector_props[] = {
 	},
 };
 
+static struct drm_property_enum_info scaling_filter_enums[] = {
+	[WDRM_SCALING_FILTER_DEFAULT]	= { .name = "Default" },
+	[WDRM_SCALING_FILTER_MEDIUM]	= { .name = "Medium" },
+	[WDRM_SCALING_FILTER_BILINEAR]	= { .name = "Bilinear" },
+	[WDRM_SCALING_FILTER_NN]	= { .name = "Nearest Neighbor" },
+	[WDRM_SCALING_FILTER_NN_IS_ONLY] = { .name = "Integer Mode Scaling" },
+	[WDRM_SCALING_FILTER_INVALID]	= { .name = "Invalid" },
+};
+
 const struct drm_property_info crtc_props[] = {
 	[WDRM_CRTC_MODE_ID] = { .name = "MODE_ID", },
 	[WDRM_CRTC_ACTIVE] = { .name = "ACTIVE", },
+	[WDRM_SCALING_FILTER] = {
+		.name = "SCALING_FILTERS",
+		.enum_values = scaling_filter_enums,
+		.num_enum_values = WDRM_SCALING_FILTER__COUNT,
+	},
 };
 
 
-- 
2.17.1