If the upscaling ratio is a complete integer, Intel display HW can
pickup special scaling mode, which can produce better non-blurry
outputs. This patch adds a check to indicate if this is such an upscaling
opportunity, while calculating the scaler config, and stores it into scaler
state.
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display.c | 21 +++++++++++++++++++
.../drm/i915/display/intel_display_types.h | 7 +++++++
2 files changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index ee54d9659c99..613130db3c05 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5388,6 +5388,19 @@ u16 skl_scaler_calc_phase(int sub, int scale, bool chroma_cosited)
#define SKL_MIN_YUV_420_SRC_W 16
#define SKL_MIN_YUV_420_SRC_H 16
+static inline bool
+scaling_ratio_integer(int src_w, int dst_w, int src_h, int dst_h)
+{
+ /* Integer mode scaling is applicable only for upscaling scenarios */
+ if (dst_w < src_w || dst_h < src_h)
+ return false;
+
+ if (dst_w % src_w == 0 && dst_h % src_h == 0)
+ return true;
+
+ return false;
+}
+
static int
skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
unsigned int scaler_user, int *scaler_id,
@@ -5422,6 +5435,14 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
return -EINVAL;
}
+ /*
+ * 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.
+ */
+ if (scaling_ratio_integer(src_w, dst_w, src_h, dst_h))
+ scaler_state->integer_scaling = true;
+
/*
* if plane is being disabled or scaler is no more required or force detach
* - free scaler binded to this plane/crtc
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 3c1a5f3e1d22..6bb32fbf3153 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -613,6 +613,13 @@ struct intel_crtc_scaler_state {
/* scaler used by crtc for panel fitting purpose */
int scaler_id;
+
+ /*
+ * Nearest-neighbor method of upscaling gieves blurless output if
+ * the upscaling ratio is a complete integer. This bool is to indicate
+ * such an opportunity.
+ */
+ bool integer_scaling;
};
/* drm_mode->private_flags */
--
2.17.1
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