drm/i915: Reuse intel_mode_vblank_start()

Replace a few hand rolled copies of intel_mode_vblank_start() with
the real thing.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240528185647.7765-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_dsb.c

@@ -328,14 +328,10 @@ static int intel_dsb_dewake_scanline(const struct intel_crtc_state *crtc_state)
 	unsigned int latency = skl_watermark_max_latency(i915, 0);
 	int vblank_start;
 
-	if (crtc_state->vrr.enable) {
+	if (crtc_state->vrr.enable)
 		vblank_start = intel_vrr_vmin_vblank_start(crtc_state);
-	} else {
-		vblank_start = adjusted_mode->crtc_vblank_start;
-
-		if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
-			vblank_start = DIV_ROUND_UP(vblank_start, 2);
-	}
+	else
+		vblank_start = intel_mode_vblank_start(adjusted_mode);
 
 	return max(0, vblank_start - intel_usecs_to_scanlines(adjusted_mode, latency));
 }

drivers/gpu/drm/i915/display/intel_vblank.c

@@ -89,9 +89,7 @@ u32 i915_get_vblank_counter(struct drm_crtc *crtc)
 
 	htotal = mode->crtc_htotal;
 	hsync_start = mode->crtc_hsync_start;
-	vbl_start = mode->crtc_vblank_start;
-	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
-		vbl_start = DIV_ROUND_UP(vbl_start, 2);
+	vbl_start = intel_mode_vblank_start(mode);
 
 	/* Convert to pixel count */
 	vbl_start *= htotal;
@@ -313,11 +311,10 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
 	htotal = mode->crtc_htotal;
 	hsync_start = mode->crtc_hsync_start;
 	vtotal = mode->crtc_vtotal;
-	vbl_start = mode->crtc_vblank_start;
+	vbl_start = intel_mode_vblank_start(mode);
 	vbl_end = mode->crtc_vblank_end;
 
 	if (mode->flags & DRM_MODE_FLAG_INTERLACE) {
-		vbl_start = DIV_ROUND_UP(vbl_start, 2);
 		vbl_end /= 2;
 		vtotal /= 2;
 	}
@@ -577,7 +574,7 @@ void intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state,
 	spin_unlock_irqrestore(&i915->drm.vblank_time_lock, irqflags);
 }
 
-static int intel_mode_vblank_start(const struct drm_display_mode *mode)
+int intel_mode_vblank_start(const struct drm_display_mode *mode)
 {
 	int vblank_start = mode->crtc_vblank_start;
 

drivers/gpu/drm/i915/display/intel_vblank.h

@@ -10,6 +10,7 @@
 #include <linux/types.h>
 
 struct drm_crtc;
+struct drm_display_mode;
 struct intel_crtc;
 struct intel_crtc_state;
 
@@ -19,6 +20,8 @@ struct intel_vblank_evade_ctx {
 	bool need_vlv_dsi_wa;
 };
 
+int intel_mode_vblank_start(const struct drm_display_mode *mode);
+
 void intel_vblank_evade_init(const struct intel_crtc_state *old_crtc_state,
 			     const struct intel_crtc_state *new_crtc_state,
 			     struct intel_vblank_evade_ctx *evade);